temp: Install xblocks-core from github branch

Author: kdmccormick

requirements/edx/base.txt

@@ -1318,7 +1318,7 @@ xblock-utils==4.0.0
     # via
     #   edx-sga
     #   xblock-poll
-xblocks-core==1.0.0
+git+https://github.com/openedx/xblocks-contrib.git@kdmccormick/xblocks-core#egg=xblocks-core
     # via -r requirements/edx/bundled.in
 xmlsec==1.3.14
     # via

requirements/edx/development.txt

@@ -2330,7 +2330,7 @@ xblock-utils==4.0.0
     #   -r requirements/edx/testing.txt
     #   edx-sga
     #   xblock-poll
-xblocks-core==1.0.0
+git+https://github.com/openedx/xblocks-contrib.git@kdmccormick/xblocks-core#egg=xblocks-core
     # via
     #   -r requirements/edx/doc.txt
     #   -r requirements/edx/testing.txt

requirements/edx/doc.txt

@@ -1658,7 +1658,7 @@ xblock-utils==4.0.0
     #   -r requirements/edx/base.txt
     #   edx-sga
     #   xblock-poll
-xblocks-core==1.0.0
+git+https://github.com/openedx/xblocks-contrib.git@kdmccormick/xblocks-core#egg=xblocks-core
     # via -r requirements/edx/base.txt
 xmlsec==1.3.14
     # via

requirements/edx/testing.txt

@@ -1739,7 +1739,7 @@ xblock-utils==4.0.0
     #   -r requirements/edx/base.txt
     #   edx-sga
     #   xblock-poll
-xblocks-core==1.0.0
+git+https://github.com/openedx/xblocks-contrib.git@kdmccormick/xblocks-core#egg=xblocks-core
     # via -r requirements/edx/base.txt
 xmlsec==1.3.14
     # via