ci: replace stale adamant-pwn/actions fork with upstream setup@v2

The adamant-pwn/actions@patch-1 fork existed only to work around the pip
externally-managed-environment error (PR competitive-verifier/actions#19,
--break-system-packages). Upstream closed that PR on 2026-04-14 as fixed and
the root issue #18 is resolved; competitive-verifier/actions/setup@v2 now
installs cleanly and supports the same package/cache-pip inputs. The fork is
~20 months stale (behind 16 commits). Move all setup steps back to @v2,
keeping the competitive-verifier>=4.1.2 pin.

Author: adamant-pwn

.github/workflows/publish.yml

@@ -89,7 +89,7 @@ jobs:
         run: python3 .verify-helper/scripts/generate_minified.py
 
       - name: Set up competitive-verifier
-        uses: adamant-pwn/actions/setup@patch-1
+        uses: competitive-verifier/actions/setup@v2
         with:
           # Floor pins the first release without the malicious polyfill.io
           # script (removed in competitive-verifier 4.1.2).

.github/workflows/verify.yml

@@ -30,7 +30,7 @@ jobs:
           submodules: recursive
 
       - name: Set up competitive-verifier
-        uses: adamant-pwn/actions/setup@patch-1
+        uses: competitive-verifier/actions/setup@v2
         with:
           # Floor pins the first release without the malicious polyfill.io
           # script (removed in competitive-verifier 4.1.2).
@@ -120,7 +120,7 @@ jobs:
         uses: competitive-verifier/actions/download-verify-artifact@v2
 
       - name: Set up competitive-verifier
-        uses: adamant-pwn/actions/setup@patch-1
+        uses: competitive-verifier/actions/setup@v2
         with:
           # Floor pins the first release without the malicious polyfill.io
           # script (removed in competitive-verifier 4.1.2).
@@ -192,7 +192,7 @@ jobs:
         run: python3 .verify-helper/scripts/generate_minified.py
 
       - name: Set up competitive-verifier
-        uses: adamant-pwn/actions/setup@patch-1
+        uses: competitive-verifier/actions/setup@v2
         with:
           # Floor pins the first release without the malicious polyfill.io
           # script (removed in competitive-verifier 4.1.2).