take meta-feeder-sdk from gitea, and run the tests on every push

github.com/worph/meta-feeder-sdk answers 404, so a clean build could not fetch
the dependency; the same tag lives on gitea-watch at the same commit (v1.7.0 =
027917c8), so only the source URL changes, in Cargo.toml and Cargo.lock.

The repo had only the image workflow; test.yml runs cargo test --locked and
clippy -D warnings, like meta-read's.

.gitea/workflows/test.yml

@@ -0,0 +1,25 @@
+# Runs the feeder's tests on every push. The repo had only the image workflow,
+# so nothing checked a change before it shipped.
+
+name: Test
+
+on:
+  push:
+    branches: ["**"]
+
+jobs:
+  rust:
+    name: cargo test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      # rust-toolchain.toml pins the channel (with clippy); rustup installs it on
+      # first use, so the action only has to provide rustup itself.
+      - uses: dtolnay/rust-toolchain@stable
+        with:
+          components: clippy
+      - uses: Swatinem/rust-cache@v2
+      - name: cargo test
+        run: cargo test --locked
+      - name: cargo clippy
+        run: cargo clippy --all-targets -- -D warnings