chore: update 0.45 migration and support notes (cosmos#10973)

## Description

Update migration and support notes related to 0.45 release.

---

### Author Checklist

*All items are required. Please add a note to the item if the item is not applicable and
please add links to any relevant follow up issues.*

I have...

- [ ] included the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] added `!` to the type prefix if API or client breaking change
- [ ] targeted the correct branch (see [PR Targeting](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#pr-targeting))
- [ ] provided a link to the relevant issue or specification
- [ ] followed the guidelines for [building modules](https://github.com/cosmos/cosmos-sdk/blob/master/docs/building-modules)
- [ ] included the necessary unit and integration [tests](https://github.com/cosmos/cosmos-sdk/blob/master/CONTRIBUTING.md#testing)
- [ ] added a changelog entry to `CHANGELOG.md`
- [ ] included comments for [documenting Go code](https://blog.golang.org/godoc)
- [ ] updated the relevant documentation or specification
- [ ] reviewed "Files changed" and left comments if necessary
- [ ] confirmed all CI checks have passed

### Reviewers Checklist

*All items are required. Please add a note if the item is not applicable and please add
your handle next to the items reviewed if you only reviewed selected items.*

I have...

- [ ] confirmed the correct [type prefix](https://github.com/commitizen/conventional-commit-types/blob/v3.0.0/index.json) in the PR title
- [ ] confirmed `!` in the type prefix if API or client breaking change
- [ ] confirmed all author checklist items have been addressed 
- [ ] reviewed state machine logic
- [ ] reviewed API design and naming
- [ ] reviewed documentation is accurate
- [ ] reviewed tests and test coverage
- [ ] manually tested (if applicable)

RELEASE_PROCESS.md

@@ -69,8 +69,9 @@ Note: not every Major Release is denoted as stable releases.
 
 Only the following major release series have a stable release status:
 
-* **0.42 «Stargate»** will be supported until 6 months after **0.43.0** is published. A fairly strict **bugfix-only** rule applies to pull requests that are requested to be included into a stable point-release.
-* **0.44** is the latest major release.
+* **0.42 «Stargate»** is supported until 2022-02-09. A fairly strict **bugfix-only** rule applies to pull requests that are requested to be included into a stable point-release.
+* **0.44** is supported until 2022-07-17. A fairly strict **bugfix-only** rule applies to pull requests that are requested to be included into a stable point-release.
+* **0.45** is the latest major release and will be supported until 6 months after **0.46.0** release.
 
 ## Stable Release Policy
 

docs/migrations/README.md

@@ -6,7 +6,8 @@ parent:
 
 # Migrations
 
-This document contains all the migration guides to update your app and modules to Cosmos SDK v0.44.
+This document contains all the migration guides to update your app and modules to the current Cosmos SDK.
 
 1. [Chain Upgrade Guide to v0.44](./chain-upgrade-guide-044.md)
-2. [REST Endpoints Migration](./rest.md)
+1. Chain Upgrade Guide to v0.45: no migration is required. See [Release Notes](https://github.com/cosmos/cosmos-sdk/blob/v0.45.0/RELEASE_NOTES.md) and [changelog](https://github.com/cosmos/cosmos-sdk/blob/v0.45.0/CHANGELOG.md) for the list of API and State Machine breaking changes.
+1. [REST Endpoints Migration](./rest.md)