ci: remove 26.3 (not yet released); 26.1 is latest

Author: sbryngelson

.github/workflows/test.yml

@@ -226,12 +226,6 @@ jobs:
             target: gpu-acc
           - nvhpc: '26.1'
             target: gpu-omp
-          - nvhpc: '26.3'
-            target: cpu
-          - nvhpc: '26.3'
-            target: gpu-acc
-          - nvhpc: '26.3'
-            target: gpu-omp
 
       fail-fast: false
     continue-on-error: true