Change -dev to full Python 3.11 version (#77)

As in the title, this PR removes the -dev part from Python 3.11 version
in CI.

Author: Secrus

.github/workflows/installer.yml

@@ -25,7 +25,7 @@ jobs:
     strategy:
       matrix:
         os: [Ubuntu, macOS, Windows]
-        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11-dev"]
+        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11"]
         args:
           - ""
           - "--preview"