DOC: Fix RTD build [skip ci]

Looks like astropy-helpers is still explicitly needed.
spacetelescope · Jan 18, 2018 · 7fb9504 · 7fb9504
1 parent 2dcd361
commit 7fb9504
Showing 1 changed file with 1 addition and 0 deletions.
diff --git a/docs/rtd-pip-requirements b/docs/rtd-pip-requirements
@@ -1,5 +1,6 @@
 numpy
 scipy
 matplotlib
+astropy-helpers
 astropy
 -e git+https://github.com/spacetelescope/synphot_refactor.git#egg=synphot