Add a forgejo workflow

.forgejo/workflows/build.yaml

@@ -0,0 +1,17 @@
+on: [push]
+jobs:
+  build:
+    runs-on: docker
+    container:
+      image: golang:alpine
+    steps:
+      - uses: actions/checkout@v4
+        run: |
+          apk add --no-cache git
+          go generate
+          go build cmd/server.go -o spaceapi
+
+      - uses: actions/upload-artifact@v2
+        with:
+          name: spaceapi
+          path: spaceapi