Rename PHP .gitignore to gitignore

Java resources may not load .gitignore, this follows suit with other
generators and uses "gitignore" (some use "gitignore.mustache").

Author: jimschubert

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPhpCodegen.java

@@ -218,7 +218,7 @@ public void processOpts() {
         // supportingFiles.add(new SupportingFile("LICENSE", "", "LICENSE"));
 
         // all PHP codegens requires Composer, it means that we need to exclude from SVN at least vendor folder
-        supportingFiles.add(new SupportingFile(".gitignore", "", ".gitignore"));
+        supportingFiles.add(new SupportingFile("gitignore", "", ".gitignore"));
     }
 
     public String getPackageName() {

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSilexServerCodegen.java

@@ -133,7 +133,7 @@ public PhpSilexServerCodegen() {
         supportingFiles.add(new SupportingFile(".htaccess", "", ".htaccess"));
 
         // remove this line when this class extends AbstractPhpCodegen
-        supportingFiles.add(new SupportingFile(".gitignore", "", ".gitignore"));
+        supportingFiles.add(new SupportingFile("gitignore", "", ".gitignore"));
     }
 
     @Override