rebase: bump github.com/prometheus/client_golang from 1.14.0 to 1.15.1

Bumps [github.com/prometheus/client_golang](https://github.com/prometheus/client_golang) from 1.14.0 to 1.15.1.
- [Release notes](https://github.com/prometheus/client_golang/releases)
- [Changelog](https://github.com/prometheus/client_golang/blob/main/CHANGELOG.md)
- [Commits](https://github.com/prometheus/client_golang/compare/v1.14.0...v1.15.1)

---
updated-dependencies:
- dependency-name: github.com/prometheus/client_golang
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

vendor/github.com/prometheus/common/expfmt/decode.go

@@ -115,32 +115,28 @@ func (d *protoDecoder) Decode(v *dto.MetricFamily) error {
 // textDecoder implements the Decoder interface for the text protocol.
 type textDecoder struct {
 	r    io.Reader
-	p    TextParser
-	fams []*dto.MetricFamily
+	fams map[string]*dto.MetricFamily
+	err  error
 }
 
 // Decode implements the Decoder interface.
 func (d *textDecoder) Decode(v *dto.MetricFamily) error {
-	// TODO(fabxc): Wrap this as a line reader to make streaming safer.
-	if len(d.fams) == 0 {
-		// No cached metric families, read everything and parse metrics.
-		fams, err := d.p.TextToMetricFamilies(d.r)
-		if err != nil {
-			return err
-		}
-		if len(fams) == 0 {
-			return io.EOF
-		}
-		d.fams = make([]*dto.MetricFamily, 0, len(fams))
-		for _, f := range fams {
-			d.fams = append(d.fams, f)
+	if d.err == nil {
+		// Read all metrics in one shot.
+		var p TextParser
+		d.fams, d.err = p.TextToMetricFamilies(d.r)
+		// If we don't get an error, store io.EOF for the end.
+		if d.err == nil {
+			d.err = io.EOF
 		}
 	}
-
-	*v = *d.fams[0]
-	d.fams = d.fams[1:]
-
-	return nil
+	// Pick off one MetricFamily per Decode until there's nothing left.
+	for key, fam := range d.fams {
+		*v = *fam
+		delete(d.fams, key)
+		return nil
+	}
+	return d.err
 }
 
 // SampleDecoder wraps a Decoder to extract samples from the metric families

vendor/github.com/prometheus/common/expfmt/fuzz.go

@@ -21,8 +21,8 @@ import "bytes"
 
 // Fuzz text metric parser with with github.com/dvyukov/go-fuzz:
 //
-//     go-fuzz-build github.com/prometheus/common/expfmt
-//     go-fuzz -bin expfmt-fuzz.zip -workdir fuzz
+//	go-fuzz-build github.com/prometheus/common/expfmt
+//	go-fuzz -bin expfmt-fuzz.zip -workdir fuzz
 //
 // Further input samples should go in the folder fuzz/corpus.
 func Fuzz(in []byte) int {

vendor/github.com/prometheus/common/expfmt/openmetrics_create.go

@@ -46,20 +46,20 @@ import (
 // missing features and peculiarities to avoid complications when switching from
 // Prometheus to OpenMetrics or vice versa:
 //
-// - Counters are expected to have the `_total` suffix in their metric name. In
-//   the output, the suffix will be truncated from the `# TYPE` and `# HELP`
-//   line. A counter with a missing `_total` suffix is not an error. However,
-//   its type will be set to `unknown` in that case to avoid invalid OpenMetrics
-//   output.
+//   - Counters are expected to have the `_total` suffix in their metric name. In
+//     the output, the suffix will be truncated from the `# TYPE` and `# HELP`
+//     line. A counter with a missing `_total` suffix is not an error. However,
+//     its type will be set to `unknown` in that case to avoid invalid OpenMetrics
+//     output.
 //
-// - No support for the following (optional) features: `# UNIT` line, `_created`
-//   line, info type, stateset type, gaugehistogram type.
+//   - No support for the following (optional) features: `# UNIT` line, `_created`
+//     line, info type, stateset type, gaugehistogram type.
 //
-// - The size of exemplar labels is not checked (i.e. it's possible to create
-//   exemplars that are larger than allowed by the OpenMetrics specification).
+//   - The size of exemplar labels is not checked (i.e. it's possible to create
+//     exemplars that are larger than allowed by the OpenMetrics specification).
 //
-// - The value of Counters is not checked. (OpenMetrics doesn't allow counters
-//   with a `NaN` value.)
+//   - The value of Counters is not checked. (OpenMetrics doesn't allow counters
+//     with a `NaN` value.)
 func MetricFamilyToOpenMetrics(out io.Writer, in *dto.MetricFamily) (written int, err error) {
 	name := in.GetName()
 	if name == "" {

vendor/github.com/prometheus/common/expfmt/text_create.go

@@ -17,7 +17,6 @@ import (
 	"bufio"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"math"
 	"strconv"
 	"strings"
@@ -44,7 +43,7 @@ const (
 var (
 	bufPool = sync.Pool{
 		New: func() interface{} {
-			return bufio.NewWriter(ioutil.Discard)
+			return bufio.NewWriter(io.Discard)
 		},
 	}
 	numBufPool = sync.Pool{

vendor/github.com/prometheus/common/expfmt/text_parse.go

@@ -142,9 +142,13 @@ func (p *TextParser) reset(in io.Reader) {
 func (p *TextParser) startOfLine() stateFn {
 	p.lineCount++
 	if p.skipBlankTab(); p.err != nil {
-		// End of input reached. This is the only case where
-		// that is not an error but a signal that we are done.
-		p.err = nil
+		// This is the only place that we expect to see io.EOF,
+		// which is not an error but the signal that we are done.
+		// Any other error that happens to align with the start of
+		// a line is still an error.
+		if p.err == io.EOF {
+			p.err = nil
+		}
 		return nil
 	}
 	switch p.currentByte {