Remove dangling reference to py-pure-pkgs

.github/workflows/build_package.yml

diff --git a/.github/workflows/build_package.yml b/.github/workflows/build_package.yml
index 8c096ba..0cd79c4 100644
--- a/.github/workflows/build_package.yml
+++ b/.github/workflows/build_package.yml
@@ -53,10 +53,6 @@
           - os: ubuntu-18.04
             build_package: py-tf-compiler-tools-pkg
             experimental: false
-          # Only needs to be built on Linux because platform independent.
-          - os: ubuntu-18.04
-            build_package: py-pure-pkgs
-            experimental: false
 
           # Windows packages.
           - os: windows-2019