rel: Prepare v0.3.0a0 release (#177)

## Which problem is this PR solving?
Prepares v0.3.0a0 release.

## Short description of the changes
- Update version to v0.3.0a0 (using `poetry version preminor`)
- Add changelog entry

## How to verify that this has the expected result
New release can be tagged and published.

Author: MikeGoldsmith

CHANGELOG.md

@@ -1,5 +1,14 @@
 # honeycomb-opentelemetry-python changelog
 
+## [0.3.0a0] - 2024-02-08
+
+### Maintenance
+
+- docs: Add Django example (#176) | @MikeGoldsmith
+- maint: Add project metadata for license and classifiers (#175) | @MikeGoldsmith
+- maint(deps-dev): bump the testing-dependencies group with 1 update (#173) | @Dependabot
+- maint(deps): update flask requirement from 2.2.2 to 2.2.5 in /examples/hello-world-flask (#171) | @Dependabot
+
 ## [0.2.4b0] - 2024-01-18
 
 ### Maintenance

pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "honeycomb-opentelemetry"
-version = "0.2.4b0"
+version = "0.3.0a0"
 description = "Honeycomb OpenTelemetry Distro for Python"
 authors = ["Honeycomb <[email protected]>"]
 readme = "README.md"