[doc][macos-ci] Update update-ci.sh script to also update pip2 packages if available [ci skip]

doc/macos-ci-install/update-ci.sh

@@ -7,6 +7,13 @@ ${brew} update
 ${brew} upgrade
 ${brew} cleanup
 
-echo "Updating python packages..."
-pip=/usr/local/bin/pip3
-${pip} list --outdated --format=freeze | grep -v '^\-e' | cut -d = -f 1  | xargs -n1 ${pip} install -U
+
+# Updates PIP packages installed
+function pipupdate() {
+  echo "Updating ${1} packages..."
+  [ ! -x "${1}" ] && return
+  ${1} list --outdated --format=freeze | grep -v '^\-e' | cut -d = -f 1  | xargs -n1 ${1} install -U;
+}
+
+pipupdate /usr/local/bin/pip3
+pipupdate /usr/local/bin/pip2