Address ResourceWarning warnings

Signed-off-by: JoeLametta <JoeLametta@users.noreply.github.com>

whipper/common/common.py

@@ -317,11 +317,11 @@ class VersionGetter:
         version = "(Unknown)"
 
         try:
-            p = asyncsub.Popen(self._args,
-                               stdin=subprocess.PIPE, stdout=subprocess.PIPE,
-                               stderr=subprocess.PIPE, close_fds=True)
-            p.wait()
-            output = asyncsub.recv_some(p, e=0, stderr=1).decode()
+            with asyncsub.Popen(self._args,
+                                stdin=subprocess.PIPE, stdout=subprocess.PIPE,
+                                stderr=subprocess.PIPE, close_fds=True) as p:
+                p.wait()
+                output = asyncsub.recv_some(p, e=0, stderr=1).decode()
             vre = self._regexp.search(output)
             if vre:
                 version = self._expander % vre.groupdict()