stdplus: Depend on googletest for support lib

This now provides some additional test case routines that require
googletest to build

Change-Id: I191705fa1b65e731308946c1eb72edc09b189bee
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/scripts/build-unit-test-docker b/scripts/build-unit-test-docker
index 60a801c..5c28aaa 100755
--- a/scripts/build-unit-test-docker
+++ b/scripts/build-unit-test-docker
@@ -272,7 +272,7 @@
         ],
     ),
     "openbmc/stdplus": PackageDef(
-        depends=["fmtlib/fmt"],
+        depends=["fmtlib/fmt", "google/googletest"],
         build_type="meson",
         config_flags=[
             "-Dexamples=false",