fix: resolve hadolint warnings and add CHANGELOG

Author: kwent

CHANGELOG.md

@@ -0,0 +1,33 @@
+# Changelog
+
+## [Unreleased]
+
+### Changed
+
+- Migrated from `rootlyhq/cli` to `rootlyhq/rootly-cli` as the underlying CLI tool
+- Dockerfile now installs `rootly-cli` from GitHub releases instead of using the deprecated `rootlyhq/cli` Docker image
+- Added `entrypoint.sh` to map GitHub Action inputs to `rootly-cli` flags
+- Command invocation changed from `rootly pulse <summary>` to `rootly pulse create <summary>`
+- Environment variable renamed from `ROOTLY_API_TOKEN` to `ROOTLY_API_KEY`
+
+## [1.2.0] - 2024-10-21
+
+### Changed
+
+- Bump actions/checkout from 4 to 6
+
+## [1.1.0] - 2023-06-01
+
+### Changed
+
+- Update README to use master branch
+- Add Dependabot for GitHub Actions
+
+## [1.0.0] - 2022-10-01
+
+### Added
+
+- Initial release
+- Support for `summary`, `api_key`, `services`, `environments`, `labels`, `source`, and `refs` inputs
+- Docker-based GitHub Action using Alpine Linux
+- CI workflows for build and lint (hadolint)

Dockerfile

@@ -1,8 +1,11 @@
 # hadolint ignore=DL3007
 FROM alpine:3.21
 
+# hadolint ignore=DL3018
 RUN apk add --no-cache curl
 
+SHELL ["/bin/ash", "-eo", "pipefail", "-c"]
+
 # Install rootly-cli from GitHub releases
 ARG ROOTLY_CLI_VERSION=latest
 RUN curl -fsSL "https://github.com/rootlyhq/rootly-cli/releases/latest/download/rootly-cli_$(curl -fsSL https://api.github.com/repos/rootlyhq/rootly-cli/releases/latest | grep '"tag_name"' | sed 's/.*"v\(.*\)".*/\1/')_linux_amd64.tar.gz" \