[packit] 0.20.2 upstream release

Upstream tag: 0.20.2
Upstream commit: 4486a88c

If you need to do any change in this pull request, you need to locally fetch the source branch of it and push it (with a fix) to your fork (as it is not possible to push to the branch created in the Packit’s fork):
```
git fetch https://src.fedoraproject.org/forks/packit/rpms/python-specfile.git refs/heads/*:refs/remotes/packit/*
git checkout packit/0.20.2-epel8-update-propose_downstream
```

plans/git_reference.py

@@ -5,10 +5,25 @@ from pathlib import Path
 
 import fmf
 
+# Set discover of specfile tests to a fixed commit
 tree_root = Path.cwd().absolute()
-node = fmf.Tree(tree_root).find("/plans")
-with node as data:
+tree = fmf.Tree(tree_root)
+main_node = tree.find("/plans")
+with main_node as data:
     data["discover"]["url"] = "https://github.com/packit/specfile.git"
     data["discover"]["ref"] = (
         subprocess.check_output(["git", "rev-parse", "HEAD"]).decode().strip()
     )
+
+
+# Set discover of packit integration tests to the current main
+packit_node = tree.find("/plans/packit-integration")
+with packit_node as data:
+    data["discover"]["ref"] = (
+        subprocess.check_output(
+            ["git", "ls-remote", "https://github.com/packit/packit", "main"]
+        )
+        .decode()
+        .strip()
+        .split()[0]
+    )