fix: envsubst when variable contains a '&'

{{cookiecutter.project_slug}}/templates/gitlab-ci-{{cookiecutter.project_slug}}.yml

@@ -366,7 +366,8 @@ stages:
   }
 
   function awkenvsubst() {
-    awk '!/# *nosubst/{while(match($0,"[$%]{[^}]*}")) {var=substr($0,RSTART+2,RLENGTH-3);val=ENVIRON[var]; gsub(/["\\]/,"\\\\&",val); gsub("\n","\\n",val);gsub("\r","\\r",val); gsub("[$%]{"var"}",val)}}1'
+    # escapes '&' char in variables for gsub
+    awk '{while(match($0,"[$%]{[^}]*}")) {var=substr($0,RSTART+2,RLENGTH-3);val=ENVIRON[var];gsub("&","\\\\&",val);gsub("[$%]{"var"}",val)}}1'
   }
 
   # login to the hosting platform