ci: add simple-claim to tests, update distributor submodule

Author: tilo-14

.github/workflows/rust-tests.yml

@@ -30,6 +30,7 @@ jobs:
           - counter/pinocchio
           - account-comparison
           - zk-id
+          - airdrop-implementations/simple-claim/program
         include:
           - example: basic-operations/native
             package: native-program-burn

README.md

@@ -6,8 +6,8 @@
 
 ### Airdrop Claim Reference Implementations
 
-* **Basic**: [**simple-claim**](https://github.com/Lightprotocol/program-examples-airdrop-implementations/simple-claim) - Distributes compressed tokens that get decompressed to SPL on claim with cliff.
-* **Advanced**: [**merkle-distributor**](https://github.com/Lightprotocol/distributor) - Distributes SPL tokens, uses compressed PDAs to track claims with linear vesting, partial claims and clawback. Based on Jito Merkle distributor and optimized with rent-free PDAs.
+* **Basic**: [**simple-claim**](./airdrop-implementations/simple-claim) - Distributes compressed tokens that get decompressed to SPL on claim with cliff.
+* **Advanced**: [**merkle-distributor**](./airdrop-implementations/distributor) - Distributes SPL tokens, uses compressed PDAs to track claims with linear vesting, partial claims and clawback. Based on Jito Merkle distributor and optimized with rent-free PDAs.
 
 For simple client side distribution visit [this example](https://github.com/Lightprotocol/example-token-distribution).