add missing link to test suite

Signed-off-by: Michael Valdron <mvaldron@redhat.com>

Author: michael-valdron

tests/README.md

@@ -18,7 +18,7 @@
 
 ### Use with testing
 
-- One can test the child samples using the [validate_devfile_schemas]() test suite by performing the following:
+- One can test the child samples using the [validate_devfile_schemas](./validate_devfile_schemas/) test suite by performing the following:
 ```sh
 export STACKS=$(bash tests/build_parents_file.sh)
 STACKS_DIR=samples/.cache bash tests/validate_devfile_schemas.sh