Add support for cargo-release

Author: eldruin

release.toml

@@ -0,0 +1,7 @@
+pre-release-replacements = [
+    {file="CHANGELOG.md", search="Unreleased", replace="{{version}}", min=1},
+    {file="CHANGELOG.md", search="\\.\\.\\.HEAD", replace="...{{tag_name}}", exactly=1},
+    {file="CHANGELOG.md", search="ReleaseDate", replace="{{date}}", min=1},
+    {file="CHANGELOG.md", search="<!-- next-header -->", replace="<!-- next-header -->\n## [Unreleased] - ReleaseDate\n", exactly=1},
+    {file="CHANGELOG.md", search="<!-- next-url -->", replace="<!-- next-url -->\n[Unreleased]: https://github.com/rust-embedded/rust-sysfs-pwm/compare/{{tag_name}}...HEAD", exactly=1},
+]