Fix resources naming scheme

The accepted practice is to retain the collection name even for a single
resource operation, like getting a specific transaction.

Also moves the PUT /transactions to /transactions/{id} which makes it
clearer that it can only be applied to an already created transaction.

.github/workflows/go.yml

@@ -1,28 +0,0 @@
-name: Go
-
-on:
-  push:
-    branches: [ "main" ]
-  pull_request:
-    branches: [ "main" ]
-
-jobs:
-  build:
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        go-version: [ '1.21', '1.22' ]
-
-    steps:
-      - uses: actions/checkout@v4
-
-      - name: Set up Go
-        uses: actions/setup-go@v5
-        with:
-          go-version: ${{ matrix.go-version }}
-
-      - name: Build
-        run: go build -v ./...
-
-      - name: Test
-        run: go test -v ./...