Drop ubuntu-1.10-x64 from CI

Author: odow

.github/workflows/ci.yml

@@ -25,9 +25,6 @@ jobs:
           - version: '1'  # The latest point-release (Windows)
             os: windows-latest
             arch: x64
-          - version: '1.10'  # 1.10 LTS (64-bit Linux)
-            os: ubuntu-latest
-            arch: x64
           - version: '1.10'  # 1.10 LTS (32-bit Linux)
             os: ubuntu-latest
             arch: x86