Add wget

Few openbmc repo uses wget to download the files from the
network therefore it is required to pull this binary into
the CI to verify builds.

Change-Id: Ibac8ab2197e63476a442f3f7dd9b6e073a64ea26
Signed-off-by: Ratan Gupta <ratagupt@in.ibm.com>
diff --git a/build-unit-test-docker.sh b/build-unit-test-docker.sh
index f22aaa3..8dbd108 100755
--- a/build-unit-test-docker.sh
+++ b/build-unit-test-docker.sh
@@ -108,7 +108,8 @@
     valgrind-dbg \
     lcov \
     libpam0g-dev \
-    xxd
+    xxd \
+    wget
 
 RUN pip install inflection
 RUN pip install pycodestyle