Add explicit catch2 dependency for tests

When I try to build the dev branch using the docker builder, the tests
target isn't properly checking out and building catch2 for the
dependency catch2.hpp. Adding this explicit dependency allowed the build
to succeed.

Signed-off-by: Mark Stemm <mark.stemm@gmail.com>

tests/CMakeLists.txt

@@ -42,6 +42,7 @@ if(FALCO_BUILD_TESTS)
            "${YAMLCPP_INCLUDE_DIR}"
            "${CIVETWEB_INCLUDE_DIR}"
            "${PROJECT_SOURCE_DIR}/userspace/falco")
+  add_dependencies(falco_test catch2)
 
   include(CMakeParseArguments)
   include(CTest)