feat(ci): use MacOS 15 for Action builds as MacOS 13 is discontinued

Author: aesedepece

.github/workflows/master.yml

@@ -127,7 +127,7 @@ jobs:
 
   Build_macOs:
     needs: [macos_helper]
-    runs-on: macos-13
+    runs-on: macos-15-intel
     steps:
       - name: Checkout
         uses: actions/checkout@v4
@@ -143,7 +143,7 @@ jobs:
           MACOSX_DEPLOYMENT_TARGET: "10.14"
           OPENSSL_STATIC: "1"
           OPENSSL_DIR: "/usr/local/openssl"
-          RUSTFLAGS: "-C target=x86_64-apple-darwin -C link-arg=-mmacosx-version-min=10.14"
+          RUSTFLAGS: "-C link-arg=-mmacosx-version-min=10.14"
         run: |
           cargo build --release -p witnet -p witnet_toolkit