chore: add string to pascal case extension (#643)

PR: #643

generator/openapi/src/main/kotlin/com/expediagroup/sdk/generators/openapi/Extensions.kt

@@ -0,0 +1,22 @@
+package com.expediagroup.sdk.generators.openapi
+
+/**
+ * This extension function converts a string to PascalCase.
+ * PascalCase is a type of identifier that consists of compound words or phrases such that each word or abbreviation begins with a capital letter.
+ * Non-alphabetic characters are ignored, and the next alphabetic character after them is capitalized.
+ *
+ * @receiver String The string to be converted to PascalCase.
+ * @return String The string converted to PascalCase.
+ */
+fun String.pascalCase(): String {
+    var capitalizeNext = true
+    val builder = StringBuilder()
+    forEach { char ->
+        when {
+            char.isLetterOrDigit().and(capitalizeNext) -> builder.append(char.uppercaseChar())
+            char.isLetterOrDigit() -> builder.append(char)
+        }
+        capitalizeNext = char.isLetter().not().or(builder.isEmpty())
+    }
+    return builder.toString()
+}

generator/openapi/src/main/kotlin/com/expediagroup/sdk/generators/openapi/OpenApiSdkGenerator.kt

@@ -107,7 +107,7 @@ class OpenApiSdkGenerator {
                     // Template specific properties
                     addAdditionalProperty("shadePrefix", product.shadePrefix)
                     addAdditionalProperty("namespace", product.namespace)
-                    addAdditionalProperty("clientClassname", namespace.replaceFirstChar { it.uppercaseChar() })
+                    addAdditionalProperty("clientClassname", namespace.pascalCase())
                     addAdditionalProperty("language", product.programmingLanguage.id)
                     addAdditionalProperty("isKotlin", ProgrammingLanguage.isKotlin(product.programmingLanguage))
                     addAdditionalProperty("isRapid", ProductFamily.isRapid(product.namespace))