libbpg: deprecate

The binaries that are built segfault on macOS Ventura.
I sent an email to upstream on 06/08/2023 but got not response
There as been no new release since some time

bpgenc is segfaulting. I ran it through lldb, here is the output:

➜  Formula git:(master) lldb bpgenc /usr/local/Homebrew/Library/Homebrew/test/support/fixtures/test.png
(lldb) target create "bpgenc"
warning: (x86_64) /usr/local/bin/bpgenc empty dSYM file detected, dSYM was created with an executable with no debug info.
Current executable set to 'bpgenc' (x86_64).
(lldb) settings set -- target.run-args  "/usr/local/Homebrew/Library/Homebrew/test/support/fixtures/test.png"
(lldb) run
Process 55734 launched: '/usr/local/bin/bpgenc' (x86_64)
Process 55734 stopped
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x200a3c040)
    frame #0: 0x0000000100074378 bpgenc`_mh_execute_header + 476024
bpgenc`:
->  0x100074378 <+476024>: vmovdqu (%rdi,%r9), %ymm6
    0x10007437e <+476030>: vpmaxub %ymm0, %ymm6, %ymm6
    0x100074382 <+476034>: vpminub %ymm1, %ymm6, %ymm6
    0x100074386 <+476038>: vmovdqu %ymm6, (%rdi,%r9)
Target 0: (bpgenc) stopped.
(lldb) bt
* thread #1, queue = 'com.apple.main-thread', stop reason = EXC_BAD_ACCESS (code=1, address=0x200a3c040)
  * frame #0: 0x0000000100074378 bpgenc`_mh_execute_header + 476024
    frame #1: 0x00000001002a428e bpgenc`unsigned int copy_count<32>(short*, short const*, long) + 136815
    frame #2: 0x0000000100042ec5 bpgenc`_mh_execute_header + 274117
    frame Homebrew#3: 0x0000000100046481 bpgenc`_mh_execute_header + 287873
    frame Homebrew#4: 0x000000010000a55f bpgenc`_mh_execute_header + 42335

Formula/lib/libbpg.rb

@@ -20,6 +20,9 @@ class Libbpg < Formula
     sha256 cellar: :any, catalina:       "f7d21d83158c5122b604bbe9641014628257dbc754fdc66ebf2ffc237bdd9893"
   end
 
+  # Test fails, email sent to upstream on Aug 2023, no response
+  deprecate! date: "2023-09-26", because: :unmaintained
+
   depends_on "cmake" => :build
   depends_on "yasm" => :build
   depends_on "jpeg-turbo"