Update generation script

Author: alejandroSuch

scripts/change-version-to

@@ -1,5 +1,12 @@
 #!/bin/bash
 
+switch_to_branch() {
+  local BRANCH=$1
+
+  git checkout -b $BRANCH
+  git pull origin $BRANCH
+}
+
 replace_files_with() {
   local VERSION=$1
 
@@ -28,7 +35,7 @@ on_success() {
   fi
 
   echo "Committing files"
-  git add Dockerfile README.txt
+  git add Dockerfile README.md
   git commit -m "$COMMIT_MSG"
   git tag -a $VERSION -m "version $VERSION"
 
@@ -60,6 +67,13 @@ if [ $# -eq 0 ]
 fi
 
 VERSION=$1
+
+if [[ $VERSION == 1.3.* ]]; then
+  switch_to_branch "1.3.x"
+else 
+  switch_to_branch "master"
+fi
+
 replace_files_with $VERSION
 build_docker $VERSION
 DOCKER_BUILD_RESULT=$?
@@ -70,4 +84,4 @@ else
   on_error
 fi
 
-
+switch_to_branch "master"