Fix Github Actions workflow

- Update MM:S / SM version targets to master (since 1.12 hasn't
been cut yet)
- Add stage to clone hl2sdk-manifests
- Restrict SDKs in configuration stage to TF2, since 'present'
errors out on SDK folders that don't exist

.github/workflows/build-on-push.yml

@@ -43,8 +43,8 @@ jobs:
           - ubuntu-20.04
           - windows-latest
         include:
-          - meta_branch: "1.11-dev"
-            sm_branch: "1.11-dev"
+          - meta_branch: "master"
+            sm_branch: "master"
             spcomp_version: "1.11.x"
 
           - os: ubuntu-20.04
@@ -114,6 +114,12 @@ jobs:
             git clone hl2sdk-proxy-repo -b $sdk hl2sdk-$sdk
           done
 
+      - name: Fetch SDK Manifests
+        uses: actions/checkout@v2
+        with:
+          repository: alliedmodders/hl2sdk-manifests
+          path: hl2sdk-manifests
+
       - name: Checkout AMBuild
         uses: actions/checkout@v3
         with:
@@ -146,7 +152,7 @@ jobs:
         run: |
           mkdir build
           cd build
-          python3 ../configure.py --sdks=present --sm-path="${{ github.workspace }}/sourcemod" --mms-path="${{ github.workspace }}/mmsource" --symbol-files --enable-optimize
+          python3 ../configure.py --sdks=tf2 --sm-path="${{ github.workspace }}/sourcemod" --mms-path="${{ github.workspace }}/mmsource" --symbol-files --enable-optimize --hl2sdk-manifest-path="${{ github.workspace }}/hl2sdk-manifests"
           ambuild
 
       - name: Build Package (Windows)