convert drone workflow to gitea actions

.drone.yml

@@ -1,27 +0,0 @@
----
-kind: pipeline
-type: docker
-name: check
-
-steps:
-  - name: lint
-    image: nixos/nix:2.20.1
-    commands:
-      - nix --extra-experimental-features 'nix-command flakes' fmt
-      - git diff --exit-code
-
-  - name: check
-    image: nixos/nix:2.20.1
-    commands:
-      - nix --extra-experimental-features 'nix-command flakes' flake check
-
-trigger:
-  event:
-    exclude:
-    - tag
-    - pull_request
----
-kind: signature
-hmac: 5af72ec77460d7d914f9177c78febed763ea1a33dc0f0e39e7599bbf8f4ad987
-
-...

.gitea/workflows/flake.yaml

@@ -0,0 +1,19 @@
+name: flake
+
+on: [push]
+
+jobs:
+  flake:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - name: Prepare for Nix installation
+        run: |
+          apt-get update
+          apt-get install -y sudo
+      - uses: cachix/install-nix-action@v26
+      - name: lint
+        run: nix fmt
+      - name: flake check
+        run: nix flake check --all-systems
+        timeout-minutes: 10