Add SSH user parameter (#1685)

* Add a configurable SSH user

* Update docs with param

* Indentation of readme

* formatting woes

* Update src/url-helper.ts

Co-authored-by: Josh Gross <joshmgross@github.com>

* Update action.yml

Co-authored-by: Josh Gross <joshmgross@github.com>

* Update genfiles

---------

Co-authored-by: Josh Gross <joshmgross@github.com>

src/git-source-settings.ts

@@ -94,6 +94,11 @@ export interface IGitSourceSettings {
    */
   sshStrict: boolean
 
+  /**
+   * The SSH user to login as
+   */
+  sshUser: string
+
   /**
    * Indicates whether to persist the credentials on disk to enable scripting authenticated git commands
    */