Update atomicwrites from 1.2.0 to 1.2.1 (#4117)

requirements/dev.txt

@@ -41,9 +41,9 @@ isort==4.3.4 \
     --hash=sha256:b9c40e9750f3d77e6e4d441d8b0266cf555e7cdabdcff33c4fd06366ca761ef8
 
 # Required by pytest
-atomicwrites==1.2.0 \
-    --hash=sha256:6b5282987b21cd79151f51caccead7a09d0a32e89c568bd9e3c4aaa7bbdf3f3a \
-    --hash=sha256:e16334d50fe0f90919ef7339c24b9b62e6abaa78cd2d226f3d94eb067eb89043
+atomicwrites==1.2.1 \
+    --hash=sha256:0312ad34fcad8fac3704d441f7b317e50af620823353ec657a53e981f92920c0 \
+    --hash=sha256:ec9ae8adaae229e4f8446952d204a3e4b5fdd2d099f9be3aaf556120135fb3ee
 attrs==18.2.0 \
     --hash=sha256:ca4be454458f9dec299268d472aaa5a11f67a4ff70093396e1ceae9c76cf4bbb \
     --hash=sha256:10cbf6e27dbce8c30807caf056c8eb50917e0eaafe86347671b57254006c3e69