feat: enable cairo 2.6.0 contract declaration

* feat: declare cairo2.6.0 contracts

* docs: add comment for rpc compatibility

* test: resolve cairo1v2 test file parsing error

* Update src/utils/hash/classHash.ts

---------

Co-authored-by: Petar Penovic <pp@spaceshard.io>

Author: PhilippeR26

__mocks__/cairo/cairo260/hello260.cairo

@@ -0,0 +1,27 @@
+// Cairo 2.6.0
+#[starknet::interface]
+trait IHelloStarknet<TContractState> {
+    fn set_name(ref self: TContractState, name1: felt252);
+    fn get_name(self: @TContractState) -> felt252;
+}
+
+
+#[starknet::contract]
+mod HelloStarknet {
+    #[storage]
+    struct Storage {
+        name: felt252,
+    }
+
+    #[abi(embed_v0)]
+    impl HelloStarknetImpl of super::IHelloStarknet<ContractState> {
+        fn set_name(ref self: ContractState, name1: felt252) {
+            assert(name1 != '', 'Enter a name');
+            self.name.write(name1);
+        }
+
+        fn get_name(self: @ContractState) -> felt252 {
+            self.name.read()
+        }
+    }
+}