update copyright notice to contributors

Author: samumantha

content/conf.py

@@ -19,8 +19,8 @@
 # -- Project information -----------------------------------------------------
 
 project = "Introduction to version control with Git"
-copyright = "CodeRefinery project"
-author = "CodeRefinery project"
+copyright = "CodeRefinery contributors"
+author = "CodeRefinery contributors"
 github_user = "coderefinery"
 github_repo_name = "git-intro"  # auto-detected from dirname if blank
 github_version = "main"