Added LTS release process doc

docs/how-to-guides/software-management/lts-release-process.md

@@ -0,0 +1,36 @@
+# LTS Release Process
+
+This page shows the steps on creating an LTS (Long Term Support) release and supporting older LTS versions. 
+
+Quick rundown of what LTS entails:
+
+- An LTS release is a feature release tagged as `LTS`
+- An LTS release occurs every 12 months
+- An LTS version is supported for at least 18 months before End of Life (EoL)
+- At maximum **two** LTS versions to support concurrently 
+
+For a more in-depth overview regarding our LTS approach, check out [RFC8 - ISIS Long Term Support](https://github.com/DOI-USGS/ISIS3/discussions/4691).
+
+## Instructions to Create a New LTS Release
+* Tag the Feature Release as `LTS`
+
+
+## Instructions to Support Older LTS Version
+_**Note: Automation of Steps 1 - 3 is TBD. The PR in Step 3 will be manually reviewed and approved before merge._
+
+### Step 1: Check the PRs for Labels
+* Any bugfix PR that addressed an issue with the `bug` label should have a `bug` label as well. 
+* Manually update PRs with the `bug` label in preparation for the next step.
+
+### Step 2: Cherry-pick the PRs
+* Pick and choose the bugfix PRs that will be brought down into the LTS version. 
+
+### Step 3: Create PR
+* Create a PR and manually make the selected bugfixes by hand. 
+* Be sure to reference the bugfix PRs in the body of this PR. 
+* Merge the PR into the LTS version of interest.
+
+### Step 4: Increment LTS Patch Version
+* Increment the patch version of the LTS build.
+* Release the newly versioned build via Anaconda.
+* Further guidelines on the [Public Release Process](../software-management/public-release-process.md)

mkdocs.yml

@@ -63,6 +63,7 @@ nav:
       - Bundle Adjustment in ISIS:         how-to-guides/image-processing/bundle-adjustment-in-isis.md
     - ISIS Demos and Workshops:            how-to-guides/isis-demos-and-workshops.md
     - Software Management:
+      - LTS Release Process:               how-to-guides/software-management/lts-release-process.md
       - Deprecation:                       how-to-guides/software-management/deprecation.md
       - Public Release Process:            how-to-guides/software-management/public-release-process.md
       - Software Support:                  how-to-guides/software-management/software-support.md