Update documentation about how to run the tests

The currently documented command

  bazel test --test_tag_filters=checks

neithers works when running it from the gerrit root dir nor when running
it from the checks plugin dir.

The new command

  bazel test //plugins/checks/...

works from the gerrit root dir and is the same command that is also used
for running the tests of other plugins (e.g. the tests for the
code-owners plugin are run by "bazel test //plugins/code-owners/...").

Change-Id: I50e2250872a4d01142d4ce0a4b645d7928ffbc48
Signed-off-by: Edwin Kempin <ekempin@google.com>
diff --git a/resources/Documentation/build.md b/resources/Documentation/build.md
index 01dd26a..719bcde 100644
--- a/resources/Documentation/build.md
+++ b/resources/Documentation/build.md
@@ -20,7 +20,7 @@
 To execute the tests run:
 
 ```
-  bazel test --test_tag_filters=@PLUGIN@
+  bazel test //plugins/@PLUGIN@/...
 ```
 
 [Back to @PLUGIN@ documentation index][index]