use dtolnay/install-buck2 (#59)

Summary:
Pull Request resolved: #59

using dtolnay/install-buck2@latest to get buck allows us to remove some boilerplate

Differential Revision:
D53090424

Privacy Context Container: L1122763

fbshipit-source-id: 262265959394b15e1977c6d6580d0b9e63c5d05f

.github/workflows/buck-build-and-test.yml

@@ -14,19 +14,11 @@ jobs:
     steps:
       - uses: actions/checkout@v4
       - uses: Swatinem/rust-cache@v2
-      - run: |
-          sudo apt-get update && sudo apt-get install opam
-          wget https://github.com/facebook/buck2/releases/download/latest/buck2-x86_64-unknown-linux-gnu.zst
-          zstd -d buck2-x86_64-unknown-linux-gnu.zst -o buck2
+      - uses: dtolnay/install-buck2@latest
+      - run: sudo apt-get update && sudo apt-get install opam
         if: matrix.os == 'ubuntu'
-      - run: |
-          brew install opam
-          wget https://github.com/facebook/buck2/releases/download/latest/buck2-x86_64-apple-darwin.zst
-          zstd -d buck2-x86_64-apple-darwin.zst -o buck2
+      - run: brew install opam
         if: matrix.os == 'macos'
-      - run: |
-          chmod +x buck2
-          sudo ln -s $(pwd)/buck2 /usr/local/bin/buck2
       - run: |
           opam init --compiler=5.1.1 --disable-sandboxing -y
           opam env | sed -e "s/ export .*//g" -e "s/'//g" -e "s/\;//g" >> $GITHUB_ENV