Update atomicwrites from 1.2.0 to 1.2.1

requirements/tests.txt

@@ -73,6 +73,6 @@ attrs==18.2.0 \
 pluggy==0.7.1 \
     --hash=sha256:6e3836e39f4d36ae72840833db137f7b7d35105079aee6ec4a62d9f80d594dd1 \
     --hash=sha256:95eb8364a4708392bae89035f45341871286a333f749c3141c20573d2b3876e1
-atomicwrites==1.2.0 \
-    --hash=sha256:6b5282987b21cd79151f51caccead7a09d0a32e89c568bd9e3c4aaa7bbdf3f3a \
-    --hash=sha256:e16334d50fe0f90919ef7339c24b9b62e6abaa78cd2d226f3d94eb067eb89043
+atomicwrites==1.2.1 \
+    --hash=sha256:0312ad34fcad8fac3704d441f7b317e50af620823353ec657a53e981f92920c0 \
+    --hash=sha256:ec9ae8adaae229e4f8446952d204a3e4b5fdd2d099f9be3aaf556120135fb3ee