Fix an issue in aer_state_initialize() of C API (#1885)

Correct C API `aer_state_initialize` to take an argument of `handler`.

* update aer_state_initialize API
* add reno

contrib/runtime/aer_runtime.cpp

@@ -23,10 +23,9 @@ void *aer_state() {
   return handler;
 };
 
-void *aer_state_initialize(void *handler) {
+void aer_state_initialize(void *handler) {
   AER::AerState *state = reinterpret_cast<AER::AerState *>(handler);
   state->initialize();
-  return handler;
 };
 
 // finalize state

contrib/runtime/aer_runtime_api.h

@@ -20,7 +20,7 @@ typedef uint_fast64_t uint_t;
 void* aer_state();
 
 // initialize aer state
-void* aer_state_initialize();
+void aer_state_initialize(void* state);
 
 // finalize state
 void aer_state_finalize(void* state);

releasenotes/notes/fix_aer_state_initialize_api-0c2c237a606648ef.yaml

@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    A function ``aer_state_initialize()`` in C API wrongly takes no argument though
+    it initializes a state created by ``aer_state()``. Example codes pass ``handler``
+    and rouboustness of C compiler allows its compilation. This commit corrects for
+    ``aer_state_initialize()`` to take an argument ``handler`` to be initialized.