Switch back to building mozilla-beta in 'next' branch

The 'next' branch should track mozilla-beta in order to get early
warnings about things that might be broken in the following ESR.

Author: ptomato

.github/workflows/build.yml

@@ -28,15 +28,15 @@ jobs:
     - uses: actions/checkout@v2
     - name: Install deps
       run: |
-        sudo apt install autoconf2.13 ccache llvm clang lld meson ninja-build -y
+        sudo apt install ccache llvm clang lld meson ninja-build -y
     - uses: actions-rs/toolchain@v1
       with:
           profile: minimal
           toolchain: stable
           override: true
           default: true
     - name: Get SM pkg
-      run: ./tools/get_sm_102.sh
+      run: ./tools/get_sm.sh
     - name: ccache cache files
       uses: actions/cache@v1.1.0
       with:
@@ -49,7 +49,6 @@ jobs:
         cd /tmp/mozjs
         cd $(ls -d */|head -n 1)
         cd js/src
-        autoconf2.13
         bash $GITHUB_WORKSPACE/tools/generic_lib.sh $GITHUB_WORKSPACE/meson.build
         mkdir _build
         cd _build