Fix typo in exception (#11)

Author: gaggle

lib/pidtree.js

@@ -58,7 +58,7 @@ function list(PID, options, callback) {
     }
 
     if (!root) {
-      callback(new Error('No maching pid found'));
+      callback(new Error('No matching pid found'));
       return;
     }
 

test/integration.js

@@ -121,7 +121,7 @@ test('should throw an error if an invalid pid is provided', async t => {
 
 test('should throw an error if the pid does not exists', async t => {
   const err = await t.throws(pidtree(65535));
-  t.is(err.message, 'No maching pid found');
+  t.is(err.message, 'No matching pid found');
 });
 
 test.cb("should use the callback if it's provided", t => {