Add GitHub Action to generate and update changelog

This commit introduces a new GitHub Action using `generate-changelog` to automate changelog creation or updates. It includes an `action.yml` for configuration, an `entrypoint.sh` script for handling inputs and execution, and a `Dockerfile` to set up the required environment.

Author: coordt

Dockerfile

@@ -0,0 +1,13 @@
+FROM python:3-slim
+
+ENV PYTHONDONTWRITEBYTECODE 1 \
+    PYTHONUNBUFFERED 1
+
+RUN  python -m venv venv && \
+     . venv/bin/activate &&  \
+     pip install --upgrade pip && \
+     venv/bin/pip install --upgrade --no-cache-dir generate-changelog==0.12.1
+
+COPY entrypoint.sh /entrypoint.sh
+
+ENTRYPOINT ["/entrypoint.sh"]

action.yml

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+name: "Run Generate Changelog"
+description: "Run generate-changelog to create or update a changelog."
+author: "Corey Oordt"
+inputs:
+  config_file:
+    description: "Path to the config file if it is not one of the defaults."
+    required: false
+    default: ""
+  starting_tag:
+    description: "Tag to generate a changelog from."
+    required: false
+    default: ""
+  skip_output_pipeline:
+    description: "Do not generate or update the CHANGELOG, but still return the release hint."
+    required: false
+    default: "false"
+  branch_override:
+    description: "Override the current branch for release hint decisions."
+    required: false
+    default: ""
+outputs:
+  release_hint:
+    description: "The suggested type of release to generate."
+branding:
+  color: "black"
+  icon: "file-text"
+runs:
+  using: "docker"
+  image: "Dockerfile"

entrypoint.sh

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+#!/bin/bash
+set -e # Increase bash strictness
+set -o pipefail
+
+function parse_boolean() {
+  local value="false"
+  value=$(echo "${1}" | awk '{print tolower($0)}')  # Convert to lowercase
+  case "$value" in
+    "true" | "yes" | "1")
+      echo 1
+      ;;
+    *)
+      echo 0
+      ;;
+  esac
+}
+
+changelog_args=("-o" "release-hint")
+
+if [[ -n ${INPUT_STARTING_TAG} ]]; then
+  changelog_args+=("-t" "${INPUT_STARTING_TAG}")
+fi
+
+if [[ -n ${INPUT_SKIP_OUTPUT_PIPELINE} && $(parse_boolean "${INPUT_SKIP_OUTPUT_PIPELINE}") -eq 1 ]]; then
+  changelog_args+=("--skip-output-pipeline")
+fi
+
+if [[ -n ${INPUT_BRANCH_OVERRIDE} ]]; then
+  changelog_args+=("-b" "${INPUT_BRANCH_OVERRIDE}")
+fi
+
+echo "[action-generate-changelog] Generating the changelog with arguments '${changelog_args[*]}'"
+
+RELEASE_HINT=$(/venv/bin/generate-changelog "${changelog_args[*]}")
+echo "::notice::Suggested release type for this branch is: ${RELEASE_HINT}"
+echo "release_hint=$RELEASE_HINT" >> $GITHUB_OUTPUT