Change git strategy for browser tests

tests/lakedrops.yml

@@ -10,6 +10,8 @@
     - 'Build Site'
 
 .test_lakedrops_theme: &test_lakedrops_theme
+  variables:
+    GIT_STRATEGY: fetch
   before_script:
     - DIR=$(dc exec -u root php pwd)
     - if [[ "${THEME_BUILD}" == "yes" && -d ${THEME_CSS_PATH} ]]; then dc cp ${THEME_CSS_PATH} php:${DIR}/${THEME_CSS_PATH}; fi