Update libmozdata from 0.1.54 to 0.1.55 (#500)

requirements.txt

@@ -1,5 +1,5 @@
 pyOpenSSL>=0.14  # Could not find a version that satisfies the requirement pyOpenSSL>=0.14; extra == "security" (from requests[security]>=2.7.0->libmozdata==0.1.43)
-libmozdata==0.1.54
+libmozdata==0.1.55
 numpy==1.16.3
 scipy==1.3.0
 scikit-learn==0.21.2