Simplify CI pipeline

.github/workflows/ci.yml

@@ -7,11 +7,8 @@ on:
 
 jobs:
   stack:
-    name: stack / ghc ${{ matrix.ghc }}
+    name: ubuntu
     runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        ghc: ["8.10.5"]
 
     steps:
     - uses: actions/checkout@v2
@@ -23,19 +20,12 @@ jobs:
         sudo apt-get install libc6:i386 libncurses5:i386 libstdc++6:i386 texlive-binaries
         sudo dpkg -i CI/rsltc_2.6.1-1_i386.deb
         rsltc -v
-    
-    - uses: haskell/actions/setup@v1
-      name: Setup Haskell Stack
-      with:
-        ghc-version: ${{ matrix.ghc }}
-        enable-stack: true
-        stack-version: 'latest'
 
     - uses: actions/[email protected]
       name: Cache ~/.stack
       with:
         path: ~/.stack
-        key: ${{ runner.os }}-${{ matrix.ghc }}-stack
+        key: ${{ runner.os }}-8.10.5-stack
 
     - name: Install dependencies
       run: |
@@ -51,7 +41,7 @@ jobs:
 
     - name: Prepare binary
       run: |
-        zip ~/linux.zip "$(stack path --system-ghc --local-install-root)/bin/rsl-language-server"
+        zip -j ~/linux.zip "$(stack path --system-ghc --local-install-root)/bin/rsl-language-server"
     
     - uses: actions/upload-artifact@v2
       with: