workflows: Rename after security fixes

In the previous two commits, security issues with these workflows were
fixed. In order for these to not be exploitable for PRs to branches that
don't have the fixes yet (including read-only branches like
nixos-unstable), these workflows are renamed, so that the old ones can
be turned off manually via GitHub interface.

Co-Authored-By: 13x1 <tori@disroot.org>
Co-Authored-By: basti564 <e3e@disroot.org>
(cherry picked from commit 5bbbc3a30b)

.github/workflows/codeowners-v2.yml

@@ -1,4 +1,4 @@
-name: Codeowners
+name: Codeowners v2
 
 # This workflow depends on two GitHub Apps with the following permissions:
 # - For checking code owners:

.github/workflows/editorconfig-v2.yml

@@ -1,4 +1,4 @@
-name: "Checking EditorConfig"
+name: "Checking EditorConfig v2"
 
 permissions:
   pull-requests: read

.github/workflows/manual-nixos-v2.yml

@@ -1,4 +1,4 @@
-name: "Build NixOS manual"
+name: "Build NixOS manual v2"
 
 permissions:
   contents: read

.github/workflows/manual-nixpkgs-v2.yml

@@ -1,4 +1,4 @@
-name: "Build Nixpkgs manual"
+name: "Build Nixpkgs manual v2"
 
 permissions:
   contents: read

.github/workflows/nix-parse-v2.yml

@@ -1,4 +1,4 @@
-name: "Check whether nix files are parseable"
+name: "Check whether nix files are parseable v2"
 
 permissions:
   pull-requests: read