implement got as WritableStream on PATCH too

followup to c080439382

index.js

@@ -110,7 +110,7 @@ function got(url, opts, cb) {
 			return;
 		}
 
-		if (opts.method === 'POST' || opts.method === 'PUT') {
+		if (opts.method === 'POST' || opts.method === 'PUT' || opts.method === 'PATCH') {
 			proxy.setWritable(req);
 			return;
 		}

test.js

@@ -174,4 +174,14 @@ describe('POST', function () {
 			})
 			.end('Hello');
 	});
+
+	it('should be a writeable stream on PATCH', function (done) {
+		got.patch('http://0.0.0.0:8081')
+			.on('error', done)
+			.on('data', function (chunk) {
+				assert.equal(chunk, 'Hello');
+				done();
+			})
+			.end('Hello');
+	});
 });