add gitignore for component unit test apps

.gitignore

@@ -21,6 +21,11 @@ GPATH
 # MacOS directory files
 .DS_Store
 
+# Components Unit Test Apps files
+components/**/build
+components/**/sdkconfig
+components/**/sdkconfig.old
+
 # Example project files
 examples/**/sdkconfig
 examples/**/sdkconfig.old