ci: use stable version of foundry

Author: shekohex

.github/workflows/foundry.yml

@@ -31,7 +31,7 @@ jobs:
       - name: Install Foundry
         uses: foundry-rs/foundry-toolchain@v1
         with:
-          version: nightly
+          version: v0.3.0
 
       - name: Install Solidity Dependencies
         run: forge soldeer update -d
@@ -59,7 +59,7 @@ jobs:
       - name: Install Foundry
         uses: foundry-rs/foundry-toolchain@v1
         with:
-          version: nightly
+          version: v0.3.0
 
       - name: Install Solidity Dependencies
         run: forge soldeer update -d