Migrate CI from CircleCI to GitHub Actions

- Add .github/workflows/ci.yml with Emacs 27-30 + snapshot on Ubuntu,
  plus macOS and Windows on Emacs 29
- Remove .circleci/config.yml
- Update CI badge in README
- Emacs snapshot job uses continue-on-error to avoid blocking on
  upstream Emacs breakage

Author: bbatsov

.circleci/config.yml

@@ -0,0 +1,40 @@
+name: CI
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+jobs:
+  test:
+    runs-on: ${{ matrix.os }}
+    continue-on-error: ${{ matrix.emacs-version == 'snapshot' }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [ubuntu-latest]
+        emacs-version: ['27.1', '28.2', '29.4', '30.1', 'snapshot']
+        include:
+          - os: macos-latest
+            emacs-version: '29.4'
+          - os: windows-latest
+            emacs-version: '29.4'
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: jcs090218/setup-emacs@master
+        with:
+          version: ${{ matrix.emacs-version }}
+
+      - uses: emacs-eldev/setup-eldev@v1
+
+      - name: Run regression tests
+        run: eldev -dtT -p test
+
+      - name: Lint
+        run: eldev lint -c
+
+      - name: Check for byte-compilation errors
+        run: eldev -dtT compile --warnings-as-errors

.github/workflows/ci.yml

@@ -1,4 +1,4 @@
-[![circleci][badge-circleci]][circleci]
+[![CI](https://github.com/clojure-emacs/clojure-mode/actions/workflows/ci.yml/badge.svg)](https://github.com/clojure-emacs/clojure-mode/actions/workflows/ci.yml)
 [![MELPA][melpa-badge]][melpa-package]
 [![MELPA Stable][melpa-stable-badge]][melpa-stable-package]
 [![NonGNU ELPA](https://elpa.nongnu.org/nongnu/clojure-mode.svg)](https://elpa.nongnu.org/nongnu/clojure-mode.html)
@@ -757,8 +757,6 @@ Distributed under the GNU General Public License; type <kbd>C-h C-c</kbd> to vie
 [melpa-package]: https://melpa.org/#/clojure-mode
 [melpa-stable-package]: https://stable.melpa.org/#/clojure-mode
 [COPYING]: https://www.gnu.org/copyleft/gpl.html
-[badge-circleci]: https://circleci.com/gh/clojure-emacs/clojure-mode.svg?style=svg
-[circleci]: https://circleci.com/gh/clojure-emacs/clojure-mode
 [CIDER]: https://github.com/clojure-emacs/cider
 [cider-nrepl]: https://github.com/clojure-emacs/cider-nrepl
 [inf-clojure]: https://github.com/clojure-emacs/inf-clojure