[CI] don't cache zmk firmware source

.gitea/workflows/build.yml

@@ -19,9 +19,6 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v3
 
-      - name: West Init
-        run: west init -l config
-
       - name: Link Directories
         run: |
           ln -s /usr/src/zephyr-3.4.0/modules modules
@@ -48,7 +45,6 @@ jobs:
             tools/
             zephyr/
             bootloader/
-            zmk/
           key: ${{ runner.os }}-build-${{ env.cache-name }}-${{ steps.hash-west.outputs.hash }}
           restore-keys: |
             ${{ runner.os }}-build-${{ env.cache-name }}-
@@ -57,6 +53,9 @@ jobs:
         timeout-minutes: 5
         continue-on-error: true
 
+      - name: West Init
+        run: west init -l config
+
       - name: West Update
         run: west update