Add document for releasing the library (#68)

Author: BrennanConroy

docs/Release.md

@@ -0,0 +1,37 @@
+# Release a new version of the library
+
+## Create the release
+* Get on the correct commit that we want to release (normally tip of main branch)
+* `git tag <tag-name>` (previous release format: v0.1.0-alpha3)
+* `git push origin <tag-name>`
+
+## Fork
+* Fork the repo at https://github.com/microsoft/vcpkg
+  - If you already have a fork, make sure it is updated to the master branch
+
+  ![image](https://user-images.githubusercontent.com/7574801/128568379-deb14ed7-1ba3-4cb7-83d2-faecf8300f21.png)
+
+* Clone your fork locally `git clone https://github.com/<fork>/vcpkg.git`
+
+## Modify vcpkg/ports/microsoft-signalr/CONTROL
+* Update the `Version`
+* Add any new features we want users to be able to add/remove (msgpack, cpprestsdk, etc.)
+
+## Modify vcpkg/ports/microsoft-signalr/portfile.cmake
+* Change the `REF` to be the tag name
+* Change the `SHA512`, this will be done in the step below
+* Update any flags we might want to set a default for in `vcpkg_configure_cmake`
+
+## Test the changes
+* Run `./bootstrap-vcpkg.bat` to get the package installer
+* Run `vcpkg install microsoft-signalr:x64-windows` to install the library
+  - The first time this runs it will fail with the wrong SHA512 and give us the correct value for the SHA512, so replace that value
+* To try out different features (defined in the CONTROL file) you can install with `vcpkg install microsoft-signalr[<feature name>]`, e.g. `<feature name>` -> `messagepack`
+* Do a smoke test that the library works, a sample app like https://github.com/halter73/SignalR-Client-Cpp-Sample explains how to do that quickly
+
+## Make a pull request
+* Commit the modified files (should be 2 files minimum)
+* After making a first commit run `./vcpkg x-add-version microsoft-signalr --overwrite-version`
+  - This will update 2 more files that vcpkg needs updated
+  - Commit the new changes
+* Submit a PR from your fork to the https://github.com/microsoft/vcpkg repo