Add upstream release bot and enable packit

.packit.yaml

@@ -0,0 +1,25 @@
+# https://packit.dev/docs/configuration/
+
+specfile_path: koji-osbuild.spec
+
+synced_files:
+    - koji-osbuild.spec
+    - .packit.yaml
+
+upstream_package_name: koji-osbuild
+downstream_package_name: koji-osbuild
+
+copy_upstream_release_description: true
+
+upstream_tag_template: v{version}
+
+actions:
+  get-current-version: bash -c "git describe --tags --abbrev=0 | sed 's|v||'"
+
+create_pr: true
+jobs:
+- job: propose_downstream
+  trigger: release
+  metadata:
+    dist_git_branches:
+      - fedora-all