cleanup: fix quoting in generate-readme.sh (#103)

* cleanup: fix quoting in generate-readme.sh

Author: mr-salty

README.md

@@ -1,6 +1,6 @@
 # Google Google Cloud C++ Client Common Libraries
 
-<!-- This file is automatically generated by ci/test-readme/$(basename "$0") -->
+<!-- This file is automatically generated by ci/test-readme/generate-readme.sh -->
 
 This repository contains common types and functions used by the
 Google Cloud C++ Client Libraries.

ci/test-readme/generate-readme.sh

@@ -31,7 +31,7 @@ _EOF_
 
 readonly DOCKERFILES_DIR="${BINDIR}/../kokoro/readme"
 
-cat <<'_EOF_'
+cat <<_EOF_
 # Google Google Cloud C++ Client Common Libraries
 
 <!-- This file is automatically generated by ci/test-readme/$(basename "$0") -->