Update aarch64 to GCC 11 (#524)

This PR updates aarch64 dependencies to use GCC 11. Follow-up to #522.

Authors:
  - Bradley Dice (https://github.com/bdice)

Approvers:
  - Gigon Bae (https://github.com/gigony)
  - Jordan Jacobelli (https://github.com/jjacobelli)

URL: #524

dependencies.yaml

@@ -58,7 +58,7 @@ dependencies:
           - matrix:
               arch: aarch64
             packages:
-              - gcc_linux-aarch64=9.*
+              - gcc_linux-aarch64=11.*
               - sysroot_linux-aarch64==2.17
       - output_types: conda
         matrices: