[chore][receiver/sqlquery] Remove stability from README title (open-t…

…elemetry#37039)

#### Description
The component stability is in the README header which makes it redundant
to be in the title as well, and the title's noted stability is now out
of date as logs are at development stability. The stability shouldn't be
included in the title.

receiver/sqlqueryreceiver/README.md

@@ -1,4 +1,4 @@
-# SQL Query Receiver (Alpha)
+# SQL Query Receiver
 
 <!-- status autogenerated section -->
 | Status        |           |