CI: Allow builds to pass even if final artifact upload fails

We are seeing higher cases of artifact upload failures
in github.  Other projects are also seeing this as has been
reported at https://github.com/actions/upload-artifact/issues/116

There is a fix that was just merged in the base library:
https://github.com/actions/toolkit/pull/675

So Hopefully we can revert this before too long.

Signed-off-by: Brennan Ashton <bashton@brennanashton.com>

.github/workflows/build.yml

@@ -168,6 +168,7 @@ jobs:
         with:
           name: linux-builds
           path: buildartifacts/
+        continue-on-error: true
 
   macOS:
     runs-on: macos-10.15
@@ -207,3 +208,4 @@ jobs:
         with:
           name: macos-builds
           path: buildartifacts/
+        continue-on-error: true