Heroku-24: Remove libgcrypt20-dev

Since:
- All of the language bindings I could find for it were unpopular and
  not actively maintained. For example:
    - Ruby: https://github.com/chrisliaw/gcrypt
      (last commit 3 years ago, 0 stars, not published to rubygems.org)
    - Python: https://framagit.org/okhin/pygcrypt/
      (last commit 6 years ago, 0 stars, close to zero PyPI downloads
      excl mirrors syncing)
- It's the dev package for the library extracted from GnuPG, and it's
  much more common for use-cases to interact with `gpg` directly. eg:
  https://github.com/vsajip/python-gnupg (8 million downloads/month)
  which interacts with the `gpg` CLI instead.

See:
https://packages.ubuntu.com/noble/libgcrypt20-dev

Towards #266.
GUS-W-15159536.

heroku-24-build/installed-packages-amd64.txt

@@ -183,7 +183,6 @@ libfribidi0
 libgcc-13-dev
 libgcc-s1
 libgcrypt20
-libgcrypt20-dev
 libgd-dev
 libgd3
 libgdbm-compat4t64
@@ -210,7 +209,6 @@ libgnutls-openssl27t64
 libgnutls28-dev
 libgnutls30t64
 libgomp1
-libgpg-error-dev
 libgpg-error0
 libgprofng0
 libgraphite2-3

heroku-24-build/installed-packages-arm64.txt

@@ -179,7 +179,6 @@ libfribidi0
 libgcc-13-dev
 libgcc-s1
 libgcrypt20
-libgcrypt20-dev
 libgd-dev
 libgd3
 libgdbm-compat4t64
@@ -203,7 +202,6 @@ libgnutls-openssl27t64
 libgnutls28-dev
 libgnutls30t64
 libgomp1
-libgpg-error-dev
 libgpg-error0
 libgprofng0
 libgraphite2-3

heroku-24-build/setup.sh

@@ -24,7 +24,6 @@ packages=(
   libevent-dev
   libexif-dev
   libffi-dev
-  libgcrypt20-dev
   libgd-dev
   libgdbm-dev
   libgnutls28-dev