Azure/GitLab: Ensure we use requirements.txt for testsuites

Given that test/py/requirements.txt has all required test modules, make
use of that rather than a manual pip install list before running our
assorted tool testsuites.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 51bd643..bff4874 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -151,7 +151,7 @@
       export USER=gitlab;
       virtualenv -p /usr/bin/python3 /tmp/venv;
       . /tmp/venv/bin/activate;
-      pip install pyelftools pytest pygit2;
+      pip install -r test/py/requirements.txt;
       export UBOOT_TRAVIS_BUILD_DIR=/tmp/sandbox_spl;
       export PYTHONPATH="${UBOOT_TRAVIS_BUILD_DIR}/scripts/dtc/pylibfdt";
       export PATH="${UBOOT_TRAVIS_BUILD_DIR}/scripts/dtc:${PATH}";