[PHP] Remove platform dependency from file path

Created by: ackintosh

PR checklist

• Read the contribution guidelines.
• Ran the shell script under ./bin/ to update Petstore sample so that CIs can verify the change. (For instance, only need to run ./bin/{LANG}-petstore.sh and ./bin/security/{LANG}-petstore.sh if updating the {LANG} (e.g. php, ruby, python, etc) code generator or {LANG} client's mustache templates). Windows batch files can be found in .\bin\windows\.
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Description of the PR

This PR fixes https://github.com/OpenAPITools/openapi-generator/issues/585

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

@@ -228,10 +228,10 @@ public abstract class AbstractPhpCodegen extends DefaultCodegen implements Codeg
         additionalProperties.put("escapedInvokerPackage", invokerPackage.replace("\\", "\\\\"));
 
         // make api and model src path available in mustache template
-        additionalProperties.put("apiSrcPath", "." + File.separator + toSrcPath(apiPackage, srcBasePath));
-        additionalProperties.put("modelSrcPath", "." + File.separator + toSrcPath(modelPackage, srcBasePath));
-        additionalProperties.put("apiTestPath", "." + File.separator + testBasePath + File.separator + apiDirName);
-        additionalProperties.put("modelTestPath", "." + File.separator + testBasePath + File.separator + modelDirName);
+        additionalProperties.put("apiSrcPath", "./" + toSrcPath(apiPackage, srcBasePath));
+        additionalProperties.put("modelSrcPath", "./" + toSrcPath(modelPackage, srcBasePath));
+        additionalProperties.put("apiTestPath", "./" + testBasePath + "/" + apiDirName);
+        additionalProperties.put("modelTestPath", "./" + testBasePath + "/" + modelDirName);
 
         // make api and model doc path available in mustache template
         additionalProperties.put("apiDocPath", apiDocPath);
@@ -255,7 +255,7 @@ public abstract class AbstractPhpCodegen extends DefaultCodegen implements Codeg
     public String toSrcPath(String packageName, String basePath) {
         packageName = packageName.replace(invokerPackage, ""); // FIXME: a parameter should not be assigned. Also declare the methods parameters as 'final'.
         if (basePath != null && basePath.length() > 0) {
-            basePath = basePath.replaceAll("[\\\\/]?$", "") + File.separatorChar; // FIXME: a parameter should not be assigned. Also declare the methods parameters as 'final'.
+            basePath = basePath.replaceAll("[\\\\/]?$", "") + '/'; // FIXME: a parameter should not be assigned. Also declare the methods parameters as 'final'.
         }
 
         String regFirstPathSeparator;
@@ -274,7 +274,7 @@ public abstract class AbstractPhpCodegen extends DefaultCodegen implements Codeg
 
         return (basePath
                 // Replace period, backslash, forward slash with file separator in package name
-                + packageName.replaceAll("[\\.\\\\/]", Matcher.quoteReplacement(File.separator))
+                + packageName.replaceAll("[\\.\\\\/]", Matcher.quoteReplacement("/"))
                 // Trim prefix file separators from package path
                 .replaceAll(regFirstPathSeparator, ""))
                 // Trim trailing file separators from the overall path