Add back global metric Meter function (#2750)

* Add back global metric Meter function

* Add change to changelog

CHANGELOG.md

@@ -8,6 +8,11 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ## [Unreleased]
 
+### Added
+
+- The `Meter` function is added back to the `go.opentelemetry.io/otel/metric/global` package.
+  This function is a convenience function equivalent to calling `global.MeterProvider().Meter(...)`. (#2750)
+
 ### Changed
 
 - Upgrade `go.opentelemetry.io/proto/otlp` in `go.opentelemetry.io/otel/exporters/otlp/otlpmetric` from `v0.12.1` to `v0.15.0`.

metric/global/global.go

@@ -19,6 +19,17 @@ import (
 	"go.opentelemetry.io/otel/metric/internal/global"
 )
 
+// Meter returns a Meter from the global MeterProvider. The
+// instrumentationName must be the name of the library providing
+// instrumentation. This name may be the same as the instrumented code only if
+// that code provides built-in instrumentation. If the instrumentationName is
+// empty, then a implementation defined default name will be used instead.
+//
+// This is short for MeterProvider().Meter(name)
+func Meter(instrumentationName string, opts ...metric.MeterOption) metric.Meter {
+	return MeterProvider().Meter(instrumentationName, opts...)
+}
+
 // MeterProvider returns the registered global trace provider.
 // If none is registered then a No-op MeterProvider is returned.
 func MeterProvider() metric.MeterProvider {