[PATCH v3] github-ci: update macos jobs to macos-15

[Junio C Hamano <gitster@pobox.com>]

GitHub from <no-reply@github.com> address keeps sending

  Subject: [Action Required] macOS 14 hosted runner image is closing down

and suggests to update to either macos-latest (macos-26) or
macos-15.  Use macos-15 for two of the four osx-* jobs, and
macos-latest for the other two jobs, which is very similar to what
.gitlab-ci does.

Because we do not care which exact version we are running, so
request macos-latest instead of naming macos-26.  If there were a
similar symbolic name for the oldest-but-still-supported version,
we would use it instead of explicitly asking for macos-15, but
because there does not appear to be any, request macos-15.  This
would require us to update these two lines once every year, which
is annoying but is manageable.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
 .github/workflows/main.yml | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index cf341d74db..7e5769f543 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -323,16 +323,16 @@ jobs:
         vector:
           - jobname: osx-clang
             cc: clang
-            pool: macos-14
+            pool: macos-15
           - jobname: osx-reftable
             cc: clang
-            pool: macos-14
+            pool: macos-latest
           - jobname: osx-gcc
             cc: gcc-13
-            pool: macos-14
+            pool: macos-latest
           - jobname: osx-meson
             cc: clang
-            pool: macos-14
+            pool: macos-15
     env:
       CC: ${{matrix.vector.cc}}
       CC_PACKAGE: ${{matrix.vector.cc_package}}

Range-diff against v2:
1:  e28c655dc1 ! 1:  1ac29e72d1 github-ci: update macos jobs to macos-15
    @@ Commit message
     
         and suggests to update to either macos-latest (macos-26) or
         macos-15.  Use macos-15 for two of the four osx-* jobs, and
    -    macos-26 for the other two jobs.
    +    macos-latest for the other two jobs, which is very similar to what
    +    .gitlab-ci does.
    +
    +    Because we do not care which exact version we are running, so
    +    request macos-latest instead of naming macos-26.  If there were a
    +    similar symbolic name for the oldest-but-still-supported version,
    +    we would use it instead of explicitly asking for macos-15, but
    +    because there does not appear to be any, request macos-15.  This
    +    would require us to update these two lines once every year, which
    +    is annoying but is manageable.
     
         Signed-off-by: Junio C Hamano <gitster@pobox.com>
     
    @@ .github/workflows/main.yml: jobs:
                - jobname: osx-reftable
                  cc: clang
     -            pool: macos-14
    -+            pool: macos-26
    ++            pool: macos-latest
                - jobname: osx-gcc
                  cc: gcc-13
     -            pool: macos-14
    -+            pool: macos-26
    ++            pool: macos-latest
                - jobname: osx-meson
                  cc: clang
     -            pool: macos-14
-- 
2.56.0-321-ga7e4057184