Remove spotless dependency on main (#54)

This PR removes the need for the main branch to be checked out
in order to build.

Signed-off-by: Marc Handalian <handalm@amazon.com>

build.gradle

@@ -96,9 +96,6 @@ ext {
 
 spotless {
     java {
-        // only apply formatting rules to updated files
-        ratchetFrom "origin/${gitDefaultBranch}"
-
         licenseHeaderFile(file('license-header'))
         googleJavaFormat().aosp()
         importOrder()