[config] prepare package for release

This PR does the following:

- adds a section to versions.yaml, please review that the new section makes sense, it didn't seem to fit in any of the other groups.
- adds doc.go

Signed-off-by: Alex Boten <aboten@lightstep.com>

config/doc.go

@@ -0,0 +1,7 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+// Package config can be used to parse a configuration file
+// that follows the JSON Schema defined by the OpenTelemetry
+// Configuration schema.
+package config // import "go.opentelemetry.io/contrib/config"

versions.yaml

@@ -83,8 +83,11 @@ module-sets:
       - go.opentelemetry.io/contrib/samplers/jaegerremote
       - go.opentelemetry.io/contrib/samplers/jaegerremote/example
       - go.opentelemetry.io/contrib/samplers/probability/consistent
+  experimental-config:
+    version: v0.1.0
+    modules:
+      - go.opentelemetry.io/contrib/config
 excluded-modules:
-  - go.opentelemetry.io/contrib/config
   - go.opentelemetry.io/contrib/instrgen
   - go.opentelemetry.io/contrib/instrgen/driver
   - go.opentelemetry.io/contrib/instrgen/testdata/interface