fix compile_pip_requirements on windows (#595)

PR #529 updated `click` to a version which depends on `colorama` on
Windows. This broke `compile_pip_requirements` on windows. This commit
resolves the issue by adding colorama as a dependency.

Co-authored-by: Alex Eagle <eagle@post.harvard.edu>

python/pip_install/repositories.bzl

diff --git a/python/pip_install/repositories.bzl b/python/pip_install/repositories.bzl
index a2ed84d..942711d 100644
--- a/python/pip_install/repositories.bzl
+++ b/python/pip_install/repositories.bzl
@@ -13,6 +13,11 @@
         "fba402a4a47334742d782209a7c79bc448911afe1149d07bdabdf480b3e2f4b6",
     ),
     (
+        "pypi__colorama",
+        "https://files.pythonhosted.org/packages/44/98/5b86278fbbf250d239ae0ecb724f8572af1c91f4a11edf4d36a206189440/colorama-0.4.4-py2.py3-none-any.whl",
+        "9f47eda37229f68eee03b24b9748937c7dc3868f906e8ba69fbcbdd3bc5dc3e2",
+    ),
+    (
         "pypi__pip",
         "https://files.pythonhosted.org/packages/47/ca/f0d790b6e18b3a6f3bd5e80c2ee4edbb5807286c21cdd0862ca933f751dd/pip-21.1.3-py3-none-any.whl",
         "78cb760711fedc073246543801c84dc5377affead832e103ad0211f99303a204",

python/pip_install/requirements.bzl

diff --git a/python/pip_install/requirements.bzl b/python/pip_install/requirements.bzl
index b040ebd..0bc382e 100644
--- a/python/pip_install/requirements.bzl
+++ b/python/pip_install/requirements.bzl
@@ -59,6 +59,7 @@
 
     deps = [
         requirement("click"),
+        requirement("colorama"),
         requirement("pip"),
         requirement("pip_tools"),
         requirement("setuptools"),