Fix mapbox-vector-tile tests

Author: pquentin

dev-requirements.txt

@@ -20,10 +20,13 @@ numpy; python_version<"3.10"
 pandas; python_version<"3.10"
 
 # Testing the 'search_mvt' API response
-mapbox-vector-tile; python_version<"3.10"
+mapbox-vector-tile
+# Python 3.7 gets an old version of mapbox-vector-tile, requiring an
+# old version of protobuf
+protobuf<4; python_version<="3.7"
 
 # Docs
 # Override Read the Docs default (sphinx<2 and sphinx-rtd-theme<0.5)
 sphinx>2
 sphinx-rtd-theme>0.5
-sphinx-autodoc-typehints
+sphinx-autodoc-typehints