Add release tooling dependencies and update README instructions

Author: kosiew

dev/release/README.md

@@ -39,6 +39,12 @@ from that branch.
 
 Releases can currently only be created by PMC members due to the permissions needed.
 
+Install the release tooling dependencies (including PyGithub) before running the changelog script:
+
+```bash
+uv sync --dev --group release --no-install-package datafusion
+```
+
 You will need a GitHub Personal Access Token. Follow
 [these instructions](https://docs.github.com/en/authentication/keeping-your-account-and-data-secure/creating-a-personal-access-token)
 to generate one if you do not already have one.

pyproject.toml

@@ -147,9 +147,11 @@ dev = [
     "pytest-asyncio>=0.23.3",
     "ruff>=0.9.1",
     "toml>=0.10.2",
-    "pygithub==2.5.0",
     "codespell==2.4.1",
 ]
+release = [
+    "pygithub==2.5.0",
+]
 docs = [
     "sphinx>=7.1.2",
     "pydata-sphinx-theme==0.8.0",