ci: add separate GitHub actions workflow for the REUSE compliance check

.github/workflows/ci.yml

@@ -154,10 +154,7 @@ jobs:
         sudo apt-get --yes --no-install-recommends install ${{ env.WEECHAT_DEPS_UBUNTU }}
         # uninstall php imagick as is causes a crash when loading php plugin (see #2009)
         sudo apt-get --yes purge php8.3-imagick
-        pipx install msgcheck reuse schemathesis
-
-    - name: Check REUSE compliancy
-      run: reuse lint
+        pipx install msgcheck schemathesis
 
     - name: Check gettext files
       run: msgcheck po/*.po

.github/workflows/reuse.yml

@@ -0,0 +1,22 @@
+# SPDX-FileCopyrightText: 2025 Sébastien Helleu <flashcode@flashtux.org>
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+name: REUSE Compliance Check
+
+on:
+  - push
+  - pull_request
+
+jobs:
+
+  test:
+
+    runs-on: ubuntu-24.04
+
+    steps:
+
+      - uses: actions/checkout@v4
+
+      - name: REUSE Compliance Check
+        uses: fsfe/reuse-action@v4