fix: resolve conflict

.gitmodules

@@ -13,3 +13,6 @@
 [submodule "lib/buffer"]
 	path = lib/buffer
 	url = https://github.com/ensdomains/buffer
+[submodule "lib/pyth-sdk-solidity"]
+	path = lib/pyth-sdk-solidity
+	url = https://github.com/pyth-network/pyth-sdk-solidity

src/libraries/LibRNSDomain.sol

@@ -21,4 +21,35 @@ library LibRNSDomain {
       hashed := keccak256(add(label, 32), mload(label))
     }
   }
+
+  /**
+   * @dev Returns the length of a given string
+   *
+   * @param s The string to measure the length of
+   * @return The length of the input string
+   */
+  function strlen(string memory s) internal pure returns (uint256) {
+    unchecked {
+      uint256 i;
+      uint256 len;
+      uint256 bytelength = bytes(s).length;
+      for (len; i < bytelength; len++) {
+        bytes1 b = bytes(s)[i];
+        if (b < 0x80) {
+          i += 1;
+        } else if (b < 0xE0) {
+          i += 2;
+        } else if (b < 0xF0) {
+          i += 3;
+        } else if (b < 0xF8) {
+          i += 4;
+        } else if (b < 0xFC) {
+          i += 5;
+        } else {
+          i += 6;
+        }
+      }
+      return len;
+    }
+  }
 }