Add changelog entries for PRs since last release (#286)

These were forgotten in the respective PRs.

Author: aabmass

opentelemetry-exporter-gcp-monitoring/CHANGELOG.md

@@ -2,6 +2,11 @@
 
 ## Unreleased
 
+- Don't use `pkg_resources.get_distribution(..).version`
+  ([#256](https://github.com/GoogleCloudPlatform/opentelemetry-operations-python/pull/256))
+- Add autoinstrumentation entrypoint for monitoring exporter
+  ([#275](https://github.com/GoogleCloudPlatform/opentelemetry-operations-python/pull/275))
+
 ## Version 1.5.0a0
 
 Released 2023-05-17

opentelemetry-exporter-gcp-trace/CHANGELOG.md

@@ -2,6 +2,9 @@
 
 ## Unreleased
 
+- Don't use `pkg_resources.get_distribution(..).version`
+  ([#256](https://github.com/GoogleCloudPlatform/opentelemetry-operations-python/pull/256))
+
 ## Version 1.5.0
 
 Released 2023-05-17

opentelemetry-resourcedetector-gcp/CHANGELOG.md

@@ -2,6 +2,11 @@
 
 ## Unreleased
 
+- Use faas.instance instead of faas.id, and bump e2e test image
+  ([#271](https://github.com/GoogleCloudPlatform/opentelemetry-operations-python/pull/271))
+- Map faas.* attributes to generic_task in resource mapping
+  ([#273](https://github.com/GoogleCloudPlatform/opentelemetry-operations-python/pull/273))
+
 ## Version 1.5.0a0
 
 Released 2023-05-17