doc: updated CONTRIBUTING.md to add release instructions

CONTRIBUTING.md

@@ -6,6 +6,118 @@ feature.
 Raise issues and feature requests in the GitHub [issue tracker](https://github.com/fujiapple852/trippy/issues) and raise
 all changes as GitHub [pull requests](https://github.com/fujiapple852/trippy/pulls).
 
+## Release instructions
+
+Instructions for releasing a new `0.xx.0` version of Trippy.
+
+Many distribution packages are managed by external maintainers, however the following are managed by the Trippy
+maintainers:
+
+- GitHub Releases
+- Crates.io
+- Docker
+- Snapcraft
+- Winget
+- Ubuntu PPA
+
+### Prerequisites
+
+- Check the MSRV (Minimum Supported Rust Version) in the `trippy` crate `Cargo.toml` is still correct.
+
+> [!NOTE]
+> The MSRV should typically be the version from around 1 year before the current date to maximise compatibility.
+
+- Update all dependencies to the latest SemVer compatible versions
+
+> [!NOTE]
+> Some distributions may not support the latest versions of all dependencies, so be conservative with updates.
+
+- Record and add an `assets/0.xx.0/demo.gif` for the new version
+- Update the `README.md` with details of the features in the new version
+- Update the `CHANGELOG.md` for the new version
+- Update the `RELEASES.md` for the new version
+- Update the version to `0.xx.0` in `Cargo.toml`, `snap/snapcraft.yaml` & `ubuntu-ppa/release.sh`
+
+### Testing
+
+Trippy is tested extensively in CI on Linux, Windows and macOS for every pull request. However, it is recommended to
+test the release binaries on all platforms before release.
+
+### Github Releases
+
+- Tag the release with the version number `0.xx.0` and push the tag to GitHub:
+
+```shell
+git tag 0.xx.0
+git push origin tag 0.xx.0
+```
+
+This will trigger the GitHub Actions workflow to build the release binaries and publish them to the GitHub release page.
+
+- Edit GitHub release page and copy the relevant sections from `RELEASES.md` and `CHANGELOG.md`. Refer to previous
+  releases for the format.
+
+### Crates.io
+
+- Publish all crates to crates.io (in order):
+
+```shell
+cargo publish trippy-dns
+cargo publish trippy-packet
+cargo publish trippy-privilege
+cargo publish trippy-tui
+cargo publish trippy
+```
+
+### Docker
+
+From the repository root directory:
+
+```shell
+docker build . -t fujiapple/trippy:0.xx.0 -t fujiapple/trippy:latest
+docker push fujiapple/trippy:0.xx.0
+docker push fujiapple/trippy:latest
+```
+
+### Snapcraft
+
+- Promote the first `0.xx.0` build to the `latest/stable` channel from the
+  Snapcraft [releases](https://snapcraft.io/trippy/releases) page
+
+### Winget
+
+- Download the latest release Windows `zip` from
+  the [GitHub releases page](https://github.com/fujiapple852/trippy/releases/latest)
+- Determine the SHA256 checksum of the release:
+
+```shell
+shasum -a 256 trippy-0.xx.0-x86_64-pc-windows-msvc.zip
+```
+
+- Update the `winget` [fork](https://github.com/fujiapple852/winget-pkgs) to the latest upstream
+- Checkout the fork and create a branch called `fujiapple852-trippy-0.xx.0`
+- Go to the Trippy directory
+
+```shell
+cd winget-pkgs/manifests/f/FujiApple/Trippy
+```
+
+- Copy the previous `0.yy.0` directory to a new directory for the new `0.xx.0` version
+- Update the `PackageVersion`, `ReleaseDate` and update all paths to the new version
+- Update the `InstallerSha256` with the checksum from the previous step
+- Update the release notes from [CHANGELOG.md](https://github.com/fujiapple852/trippy/blob/master/CHANGELOG.md)
+- Commit the changes with message:
+
+```text
+update fujiapple852/trippy to 0.xx.0
+```
+
+- Push the branch to the fork and create a pull request against the upstream `winget-pkgs` repository
+
+### Ubuntu PPA
+
+See the Ubuntu PPA [README.md](https://github.com/fujiapple852/trippy/blob/master/ubuntu-ppa/README.md)
+
 ## Help wanted
 
 There are several the issues tagged