workflows: gc store and purge old caches

Signed-off-by: Ophestra <cat@gensokyo.uk>

.gitea/workflows/test.yml

@@ -32,6 +32,11 @@ jobs:
         with:
           primary-key: flake-check-${{ runner.os }}-${{ hashFiles('**/*.nix') }}
           restore-prefixes-first-match: flake-check-${{ runner.os }}-
+          gc-max-store-size-linux: 1073741824
+          purge: true
+          purge-prefixes: flake-check-${{ runner.os }}-
+          purge-created: 60
+          purge-primary-key: never
 
       - name: Run tests
         run: |
@@ -72,6 +77,11 @@ jobs:
         with:
           primary-key: build-dist-${{ runner.os }}-${{ hashFiles('**/*.nix') }}
           restore-prefixes-first-match: build-dist-${{ runner.os }}-
+          gc-max-store-size-linux: 1073741824
+          purge: true
+          purge-prefixes: build-dist-${{ runner.os }}-
+          purge-created: 60
+          purge-primary-key: never
 
       - name: Build for test
         id: build-test