fix: add missing click dependency

Click is used in parts of the CI scripts (see run_config/fvp-linux.tc
for instance), add it back as part of a new dependency group. Future
dependencies that are required only in CI should be added to the
``ci`` dependency group.

Change-Id: I5da7fea703495dd4006d86334626f126a850bb10
Signed-off-by: Harrison Mutai <harrison.mutai@arm.com>
diff --git a/pyproject.toml b/pyproject.toml
index 7d748c5..b99f777 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -16,3 +16,5 @@
 sphinx-rtd-theme = "^1.1.1"
 pip-tools = "^6.4.0"
 
+[tool.poetry.group.ci.dependencies]
+click = "^8.1.3"