CI: Update macos workflow to latest macos

Looks like macos-13 is now depricated so replace those with macos-15 and
macos-26.

Author: praveenkumar

.github/workflows/macos-installer.yml

@@ -17,8 +17,8 @@ jobs:
       fail-fast: false
       matrix:
         os:
-          - macOS-13
-          - macOS-14
+          - macOS-15-intel
+          - macOS-15
         go:
           - '1.24'
     steps:

.github/workflows/make-check.yml

@@ -11,8 +11,8 @@ jobs:
       fail-fast: false
       matrix:
         os:
-          - macOS-13
-          - macOS-14
+          - macOS-15
+          - macOS-26
           - ubuntu-latest
           - ubuntu-22.04
         go: