Use jinja templating for the release notes

doc/topics/releases/templates/3006.0.md.template

@@ -0,0 +1,59 @@
+(release-3006.0)=
+# Salt 3006.0 release notes - Codename Sulfur
+
+## Onedir packaging
+
+Going forward from the 3006.0 release, the Salt Project will only provide onedir
+packages to install or upgrade Salt. The classic, non-onedir packages will not
+be provided for supported operating systems. See [Upgrade to onedir](https://docs.saltproject.io/salt/install-guide/en/latest/topics/upgrade-to-onedir.html)
+in the [Salt Install Guide](https://docs.saltproject.io/salt/install-guide/en/latest) for information about upgrading from the classic packages to the onedir
+packages.
+
+
+## Dropping support for Python 3.5 and 3.6
+
+Python 3.5 and 3.6 will no longer be supported by Salt since they
+are end of life. Going forward our policy will be to align with Python's
+supported versions. See [Salt support for Python versions](https://docs.saltproject.io/salt/install-guide/en/latest/topics/salt-python-version-support.html)
+for more information.
+
+
+## All salt-api functionality disabled by default
+
+All netapi clients, which provide the functionality to ``salt-api``, will now
+be disabled by default as a security precaution. If you use ``salt-api``, you
+must add the new ``netapi_enable_clients`` option to your salt master config.
+This is a breaking change and the ``salt-api`` will not function without this
+new configuration option. See [Enabling netapi client interfaces](https://docs.saltproject.io/en/3006.0/topics/netapi/netapi-enable-clients.html#netapi-enable-clients)
+for more information.
+
+
+## How do I migrate to the onedir packages?
+
+The migration path from the classic, non-onedir packages to the onedir packages
+will include:
+
+* Repo File: You need to update your repo file to point to the new repo paths
+  for your platform. After the repo file is updated, upgrade your Salt packages.
+* Pip packages: You need to ensure any 3rd party pip packages are installed in
+  the correct onedir path. This can be accomplished in two ways:
+
+  * ``salt-pip install <package name>``
+  * Using the ``pip.installed`` Salt state.
+
+To install python packages into the system python environment, user's must now
+provide the ``pip_bin`` or ``bin_env`` to the pip state module.
+
+For example:
+
+```yaml
+lib-foo:
+  pip.installed:
+    - pip_bin: /usr/bin/pip3
+lib-bar:
+  pip.installed:
+    - bin_env: /usr/bin/python3
+```
+
+## Changelog
+{{ changelog }}

tools/changelog.py

@@ -12,6 +12,7 @@ import re
 import sys
 import textwrap
 
+from jinja2 import Environment, FileSystemLoader
 from ptscripts import Context, command_group
 
 from tools.utils import REPO_ROOT, Version
@@ -309,17 +310,26 @@ def update_release_notes(
         versions = {}
         for fpath in pathlib.Path("doc/topics/releases").glob("*.md"):
             versions[(Version(fpath.stem))] = fpath
-        release_notes_path = versions[sorted(versions)[-1]]
+        latest_version = sorted(versions)[-1]
+        release_notes_path = versions[latest_version]
+        version = ".".join(str(part) for part in latest_version.release)
     else:
+        version = ".".join(str(part) for part in salt_version.release)
         release_notes_path = pathlib.Path("doc/topics/releases") / "{}.md".format(
-            ".".join(str(part) for part in salt_version.release)
+            version
         )
-    if not release_notes_path.exists():
-        release_notes_path.write_text(
+    template_release_path = (
+        release_notes_path.parent / "templates" / f"{version}.md.template"
+    )
+    if not template_release_path.exists():
+        template_release_path.write_text(
             textwrap.dedent(
                 f"""\
                 (release-{salt_version})=
                 # Salt {salt_version} release notes - UNRELEASED
+
+                ## Changelog
+                {{{{ changelog }}}}
                 """
             )
         )
@@ -334,7 +344,15 @@ def update_release_notes(
     tmp_release_notes_path = (
         release_notes_path.parent / f"{release_notes_path.name}.tmp"
     )
-    tmp_release_notes_path.write_text(f"{existing}\n## Changelog\n{changes}")
+
+    # render the release notes jinja template
+    environment = Environment(loader=FileSystemLoader(template_release_path.parent))
+    template = environment.get_template(template_release_path.name)
+    content = template.render(
+        {"changelog": changes},
+    )
+
+    tmp_release_notes_path.write_text(content)
     try:
         contents = tmp_release_notes_path.read_text().strip()
         if draft: