title: Build a protocol buffer project with Intellij. No such file or directory when the file does exit
body: <p>I'm working on a protocol buffer project with Intellij. While trying to add a maven plugin to compile the .proto file, it says </p>
  
  <p>"C:\Users\E24131\IdealProjects\testProtobuf\src\main\test.proto
  Error: No such file or directory"</p>
  
  <ol>
  <li>I checked the filepath. The file exists.</li>
  <li>The file type in Intellij can recognize the *.proto file.</li>
  </ol>
  
  <p>Thanks in advance.</p>