unit-test: clang tools 6.0 -> 8

Change-Id: I80be4738f012423e94686e0442055e54fd84a807
Signed-off-by: William A. Kennington III <wak@google.com>
diff --git a/build-unit-test-docker.sh b/build-unit-test-docker.sh
index 4c19675..d698d3e 100755
--- a/build-unit-test-docker.sh
+++ b/build-unit-test-docker.sh
@@ -199,10 +199,10 @@
     git \
     dbus \
     iputils-ping \
-    clang-6.0 \
-    clang-format-6.0 \
-    clang-tidy-6.0 \
-    clang-tools-6.0 \
+    clang-8 \
+    clang-format-8 \
+    clang-tidy-8 \
+    clang-tools-8 \
     iproute2 \
     libnl-3-dev \
     libnl-genl-3-dev \