Update module prometheus/client_golang to v1.6.0 (#463)

Update module prometheus/client_golang to v1.6.0

Reviewed-on: https://kolaente.dev/vikunja/api/pulls/463

vendor/google.golang.org/protobuf/internal/fieldnum/wrappers_gen.go

@@ -0,0 +1,52 @@
+// Copyright 2019 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Code generated by generate-protos. DO NOT EDIT.
+
+package fieldnum
+
+// Field numbers for google.protobuf.DoubleValue.
+const (
+	DoubleValue_Value = 1 // optional double
+)
+
+// Field numbers for google.protobuf.FloatValue.
+const (
+	FloatValue_Value = 1 // optional float
+)
+
+// Field numbers for google.protobuf.Int64Value.
+const (
+	Int64Value_Value = 1 // optional int64
+)
+
+// Field numbers for google.protobuf.UInt64Value.
+const (
+	UInt64Value_Value = 1 // optional uint64
+)
+
+// Field numbers for google.protobuf.Int32Value.
+const (
+	Int32Value_Value = 1 // optional int32
+)
+
+// Field numbers for google.protobuf.UInt32Value.
+const (
+	UInt32Value_Value = 1 // optional uint32
+)
+
+// Field numbers for google.protobuf.BoolValue.
+const (
+	BoolValue_Value = 1 // optional bool
+)
+
+// Field numbers for google.protobuf.StringValue.
+const (
+	StringValue_Value = 1 // optional string
+)
+
+// Field numbers for google.protobuf.BytesValue.
+const (
+	BytesValue_Value = 1 // optional bytes
+)