Use packit to automate ima-evm-utils releasing

Follow [1] to use packit to automate releasing ima-evm-utils. After finishing
one-time setting up, when there is a new upstream release, here's the
new process of releasing a new version in Fedora,

1. https://release-monitoring.org/ finds a new upstream and notify
   packit

2. packit: automatically create PRs to propose new release for different
   Fedora releases;  also upload new tarballs into lookaside cache.

3. Maintainer: review(, modify) and merge the PR

4. packit: create a koji build

5. packit: create a Bodhi update

So maintainers only need to do step 3 manually and all the repetitive
work can be left to packit to handle.

After the PR gets merged, two more things need to be done [2],
 - Create a Fedora mapping for the upstream project in
   https://release-monitoring.org/projects
 - Set Monitoring status on the left side at
   https://src.fedoraproject.org/rpms/ima-evm-utils to Monitoring

[1] https://packit.dev/docs/fedora-releases-guide/dist-git-onboarding
[2] https://packit.dev/docs/fedora-releases-guide/dist-git-onboarding#2-monitoring-of-the-package

Signed-off-by: Coiby Xu <coxu@redhat.com>

.gitignore

@@ -1 +1,2 @@
 /ima-evm-utils-*.tar.gz
+prepare_sources_result*/

.packit.yaml

@@ -0,0 +1,34 @@
+# See the documentation for more information:
+# https://packit.dev/docs/configuration/
+
+specfile_path: ima-evm-util.spec
+
+# add or remove files that should be synced
+files_to_sync:
+    - .packit.yaml
+
+# name in upstream package repository or registry (e.g. in PyPI)
+upstream_package_name: ima-evm-utils
+# downstream (Fedora) RPM package name
+downstream_package_name: ima-evm-utils
+
+jobs:
+  # This is triggered by https://release-monitoring.org/
+  - job: pull_from_upstream
+    trigger: release
+    dist_git_branches:
+      - fedora-all
+
+  # This is triggered at Fedora dist-git for creating koji build after
+  # PR in src.fedoraproject.org been merged.
+  - job: koji_build
+    trigger: commit
+    allowed_pr_authors: ["all_committers"]
+    dist_git_branches:
+      - fedora-all
+
+  # This is triggered at Fedora messaging bus about koji build finished.
+  - job: bodhi_update
+    trigger: commit
+    allowed_builders: ["all_committers"]
+    dist_git_branches: