Update build workflow to use HDLBuild for dependency management and building

.github/workflows/build.yml

@@ -1,4 +1,4 @@
-name: Manuelles Build mit ISE
+name: Build with HDLBuild
 
 on:
   workflow_dispatch:
@@ -14,6 +14,7 @@ jobs:
 
       - name: Build
         run: |
-          cd "$GITHUB_WORKSPACE/build"
-          make
+          cd "$GITHUB_WORKSPACE"
+          hdlbuild dep
+          hdlbuild build