Add zk-nullifier example and move zk-id to zk/ folder

Author: tilo-14

.github/workflows/rust-tests.yml

@@ -29,7 +29,8 @@ jobs:
           - counter/native
           - counter/pinocchio
           - account-comparison
-          - zk-id
+          - zk/zk-id
+          - zk/zk-nullifier
           - airdrop-implementations/simple-claim/program
         include:
           - example: basic-operations/native
@@ -51,10 +52,10 @@ jobs:
           example: ${{ matrix.example }}
           solana-cli-version: ${{ env.SOLANA_CLI_VERSION }}
           rust-toolchain: ${{ env.RUST_TOOLCHAIN }}
-          install-circom: ${{ matrix.example == 'zk-id' }}
+          install-circom: ${{ startsWith(matrix.example, 'zk/') || startsWith(matrix.example, 'zk/') }}
 
       - name: Setup ZK circuits
-        if: matrix.example == 'zk-id'
+        if: startsWith(matrix.example, 'zk/') || startsWith(matrix.example, 'zk/')
         working-directory: ${{ matrix.example }}
         run: ./scripts/setup.sh