config: support v0.3 of the config schema (#6126)

Adding support for [v0.3.0
release](https://github.com/open-telemetry/opentelemetry-configuration/releases/tag/v0.3.0)
of otel configuration.

As part of the changes, i moved the unmarshaling code into its of file
for each format (config_json.go and config_yaml.go) to ensure the
resulting struct is consistent. Validated this through unit tests

---------

Signed-off-by: Alex Boten <223565+codeboten@users.noreply.github.com>
Co-authored-by: Tyler Yahn <MrAlias@users.noreply.github.com>
Co-authored-by: Damien Mathieu <42@dmathieu.com>

CHANGELOG.md

@@ -33,6 +33,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - The deprecated `go.opentelemetry.io/contrib/instrumentation/gopkg.in/macaron.v1/otelmacaron` package is removed. (#6186)
 - The deprecated `go.opentelemetry.io/contrib/samplers/aws/xray` package is removed. (#6187)
 
+### Changed
+
+- Updated `go.opentelemetry.io/contrib/config` to use the [v0.3.0](https://github.com/open-telemetry/opentelemetry-configuration/releases/tag/v0.3.0) release of schema which includes backwards incompatible changes. (#6126)
+
 <!-- Released section -->
 <!-- Don't change this section unless doing release -->
 

Makefile

@@ -309,7 +309,7 @@ update-all-otel-deps:
 OPENTELEMETRY_CONFIGURATION_JSONSCHEMA_SRC_DIR=tmp/opentelememetry-configuration
 
 # The SHA matching the current version of the opentelemetry-configuration schema to use
-OPENTELEMETRY_CONFIGURATION_JSONSCHEMA_VERSION=v0.2.0
+OPENTELEMETRY_CONFIGURATION_JSONSCHEMA_VERSION=v0.3.0
 
 # Cleanup temporary directory
 genjsonschema-cleanup:
@@ -326,6 +326,7 @@ genjsonschema: genjsonschema-cleanup $(GOJSONSCHEMA)
 		--capitalization OTLP \
 		--struct-name-from-title \
 		--package config \
+		--only-models \
 		--output ${GENERATED_CONFIG} \
 		${OPENTELEMETRY_CONFIGURATION_JSONSCHEMA_SRC_DIR}/schema/opentelemetry_configuration.json
 	@echo Modify jsonschema generated files.

config/config.go

@@ -150,3 +150,11 @@ func ParseYAML(file []byte) (*OpenTelemetryConfiguration, error) {
 
 	return &cfg, nil
 }
+
+func toStringMap(pairs []NameStringValuePair) map[string]string {
+	output := make(map[string]string)
+	for _, v := range pairs {
+		output[v.Name] = *v.Value
+	}
+	return output
+}