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/procfs/net_softnet.go

@@ -27,8 +27,9 @@ import (
 // For the proc file format details,
 // See:
 // * Linux 2.6.23 https://elixir.bootlin.com/linux/v2.6.23/source/net/core/dev.c#L2343
-// * Linux 4.17 https://elixir.bootlin.com/linux/v4.17/source/net/core/net-procfs.c#L162
-// and https://elixir.bootlin.com/linux/v4.17/source/include/linux/netdevice.h#L2810.
+// * Linux 2.6.39 https://elixir.bootlin.com/linux/v2.6.39/source/net/core/dev.c#L4086
+// * Linux 4.18 https://elixir.bootlin.com/linux/v4.18/source/net/core/net-procfs.c#L162
+// * Linux 5.14 https://elixir.bootlin.com/linux/v5.14/source/net/core/net-procfs.c#L169
 
 // SoftnetStat contains a single row of data from /proc/net/softnet_stat.
 type SoftnetStat struct {
@@ -38,6 +39,18 @@ type SoftnetStat struct {
 	Dropped uint32
 	// Number of times processing packets ran out of quota.
 	TimeSqueezed uint32
+	// Number of collision occur while obtaining device lock while transmitting.
+	CPUCollision uint32
+	// Number of times cpu woken up received_rps.
+	ReceivedRps uint32
+	// number of times flow limit has been reached.
+	FlowLimitCount uint32
+	// Softnet backlog status.
+	SoftnetBacklogLen uint32
+	// CPU id owning this softnet_data.
+	Index uint32
+	// softnet_data's Width.
+	Width int
 }
 
 var softNetProcFile = "net/softnet_stat"
@@ -66,22 +79,57 @@ func parseSoftnet(r io.Reader) ([]SoftnetStat, error) {
 	for s.Scan() {
 		columns := strings.Fields(s.Text())
 		width := len(columns)
+		softnetStat := SoftnetStat{}
 
 		if width < minColumns {
 			return nil, fmt.Errorf("%d columns were detected, but at least %d were expected", width, minColumns)
 		}
 
-		// We only parse the first three columns at the moment.
-		us, err := parseHexUint32s(columns[0:3])
-		if err != nil {
-			return nil, err
+		// Linux 2.6.23 https://elixir.bootlin.com/linux/v2.6.23/source/net/core/dev.c#L2347
+		if width >= minColumns {
+			us, err := parseHexUint32s(columns[0:9])
+			if err != nil {
+				return nil, err
+			}
+
+			softnetStat.Processed = us[0]
+			softnetStat.Dropped = us[1]
+			softnetStat.TimeSqueezed = us[2]
+			softnetStat.CPUCollision = us[8]
 		}
 
-		stats = append(stats, SoftnetStat{
-			Processed:    us[0],
-			Dropped:      us[1],
-			TimeSqueezed: us[2],
-		})
+		// Linux 2.6.39 https://elixir.bootlin.com/linux/v2.6.39/source/net/core/dev.c#L4086
+		if width >= 10 {
+			us, err := parseHexUint32s(columns[9:10])
+			if err != nil {
+				return nil, err
+			}
+
+			softnetStat.ReceivedRps = us[0]
+		}
+
+		// Linux 4.18 https://elixir.bootlin.com/linux/v4.18/source/net/core/net-procfs.c#L162
+		if width >= 11 {
+			us, err := parseHexUint32s(columns[10:11])
+			if err != nil {
+				return nil, err
+			}
+
+			softnetStat.FlowLimitCount = us[0]
+		}
+
+		// Linux 5.14 https://elixir.bootlin.com/linux/v5.14/source/net/core/net-procfs.c#L169
+		if width >= 13 {
+			us, err := parseHexUint32s(columns[11:13])
+			if err != nil {
+				return nil, err
+			}
+
+			softnetStat.SoftnetBacklogLen = us[0]
+			softnetStat.Index = us[1]
+		}
+		softnetStat.Width = width
+		stats = append(stats, softnetStat)
 	}
 
 	return stats, nil