Bump protobuf from v27.2 to v28.0

protobuf v27.2 uses Zlib 1.2.11, which produces the error below when
building on macOS with Xcode 16.4 and Clang 17. See:

- madler/zlib#895
- llvm/llvm-project#74676

protobuf v28.0 uses Zlib 1.3.1 via protocolbuffers/protobuf#17029, which
resolves the issue.

```txt
$ bazel build //...

Starting local Bazel server and connecting to it...
INFO: Analyzed 2 targets (113 packages loaded, 2278 targets configured).

INFO: From Compiling adler32.c [for tool]:
In file included from external/zlib/adler32.c:8:
external/zlib/zutil.h:170:11: warning: 'OS_CODE' macro redefined [-Wmacro-redefined]
  170 | #  define OS_CODE 19
      |           ^
external/zlib/zutil.h:141:11: note: previous definition is here
  141 | #  define OS_CODE  7
      |           ^
1 warning generated.

[ ...snip OS_CODE warning from crc32.c:30... ]

ERROR: external/zlib/BUILD.bazel:37:11:
  Compiling zutil.c [for tool] failed: (Exit 1): cc_wrapper.sh failed:
  error executing CppCompile command (from target @@zlib//:zlib)
  external/local_config_cc/cc_wrapper.sh -U_FORTIFY_SOURCE
    -fstack-protector -Wall -Wthread-safety -Wself-assign
    -Wunused-but-set-parameter -Wno-free-nonheap-object
    -fcolor-diagnostics ... (remaining 33 arguments skipped)

ERROR: external/zlib/BUILD.bazel:37:11:
Compiling zutil.c [for tool] failed: (Exit 1): wrapped_clang failed:
error executing command (from target @zlib//:zlib)
external/local_config_cc/wrapped_clang '-D_FORTIFY_SOURCE=1'
-fstack-protector -fcolor-diagnostics -Wall -Wthread-safety
-Wself-assign -fno-omit-frame-pointer -g0 -O2 -DNDEBUG
'-DNS_BLOCK_ASSERTIONS=1' ... (remaining 35 arguments skipped)

[ ...snip OS_CODE warning from zutil.c:8... ]

In file included from external/zlib/zutil.c:10:
In file included from external/zlib/gzguts.h:21:
In file included from
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/stdio.h:61:
/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/_stdio.h:318:7:
error: expected identifier or '('
  318 | FILE    *fdopen(int, const char *) __DARWIN_ALIAS_STARTING(__MAC_10_6, __IPHONE_2_0, __DARWIN_ALIAS(fdopen));
      |          ^
external/zlib/zutil.h:147:33: note: expanded from macro 'fdopen'
  147 | #        define fdopen(fd,mode) NULL /* No fdopen() */
      |                                 ^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/lib/clang/17/include/__stddef_null.h:26:16:
note: expanded from macro 'NULL'
   26 | #define NULL ((void*)0)
      |                ^

[ ...snip two more error messages pointing into __stddef_null.h:26... ]

1 warning and 3 errors generated.

ERROR: external/com_frobozz_rules_magic/src/com/frobozz/magic/BUILD:3:12
  Building external/com_frobozz_rules_magic/src/com/frobozz/magic/EmitDigestsWorker.jar
  (1 source file) [for tool] failed: (Exit 1): cc_wrapper.sh failed:
  [ ...snip repeated CppCompile command error... ]
```

Author: mbland

rules_magic/magic/deps.bzl

@@ -33,9 +33,9 @@ def rules_magic_deps():
     maybe(
         http_archive,
         name = "com_google_protobuf",
-        sha256 = "e4ff2aeb767da6f4f52485c2e72468960ddfe5262483879ef6ad552e52757a77",
-        strip_prefix = "protobuf-27.2",
-        url = "https://github.com/protocolbuffers/protobuf/archive/refs/tags/v27.2.tar.gz",
+        sha256 = "13e7749c30bc24af6ee93e092422f9dc08491c7097efa69461f88eb5f61805ce",
+        strip_prefix = "protobuf-28.0",
+        url = "https://github.com/protocolbuffers/protobuf/archive/refs/tags/v28.0.tar.gz",
     )
 
     maybe(