unexpected method 'appcast' called on Cask font-firacode-nerd-font.

[jerrythomas]

Verification

• I understand that if I ignore these instructions, my issue may be closed without review.
• I have retried my command with --force.
• I ran brew update-reset && brew update and retried my command.
• I ran brew doctor, fixed as many issues as possible and retried my command.
• I have checked the instructions for reporting bugs.
• I made doubly sure this is not a checksum does not match / SHA256 mismatch error (do not open an issue before trying to open a PR to fix first).

Description of issue

I am seeing multiple errors with the message "unexpected method 'appcast' called". These look to be issues in specific casks and not in home brew itself.

Error: Unexpected method 'appcast' called on Cask boostnote.
Follow the instructions here:
  https://github.com/Homebrew/homebrew-cask#reporting-bugs
Error: Unexpected method 'appcast' called on Cask font-firacode-nerd-font.
Follow the instructions here:
  https://github.com/Homebrew/homebrew-cask#reporting-bugs

On running brew doctor

brew doctor 
Error: Unexpected method 'appcast' called on Cask boostnote.
Follow the instructions here:
  https://github.com/Homebrew/homebrew-cask#reporting-bugs
Error: Unexpected method 'appcast' called on Cask font-firacode-nerd-font.
Follow the instructions here:
  https://github.com/Homebrew/homebrew-cask#reporting-bugs
Error: Unexpected method 'appcast' called on Cask boostnote.
Follow the instructions here:
  https://github.com/Homebrew/homebrew-cask#reporting-bugs
Error: Unexpected method 'appcast' called on Cask font-firacode-nerd-font.
Follow the instructions here:
  https://github.com/Homebrew/homebrew-cask#reporting-bugs

Command that failed

brew upgrade

Output of command with --verbose --debug

/usr/local/Homebrew/Library/Homebrew/brew.rb (Cask::CaskLoader::FromInstalledPathLoader): loading boostnote
Error: Unexpected method 'appcast' called on Cask boostnote.
Follow the instructions here:
  https://github.com/Homebrew/homebrew-cask#reporting-bugs


```text
/usr/local/Homebrew/Library/Homebrew/brew.rb (Cask::CaskLoader::FromAPILoader): loading font-fira-code-nerd-font
/usr/local/Homebrew/Library/Homebrew/brew.rb (Cask::CaskLoader::FromInstalledPathLoader): loading font-firacode-nerd-font
Error: Unexpected method 'appcast' called on Cask font-firacode-nerd-font.
Follow the instructions here:
  https://github.com/Homebrew/homebrew-cask#reporting-bugs

### Output of `brew doctor` and `brew config`

```shell
HOMEBREW_VERSION: 4.3.5-120-ge8430b2
ORIGIN: https://github.com/Homebrew/brew
HEAD: e8430b25a1d1321f32e5093d62b57b5cb7cfb3c3
Last commit: 12 hours ago
Core tap HEAD: 8c38e412dbea12a56a7825cb8c3753a60ecb3991
Core tap last commit: 30 minutes ago
Core tap JSON: 17 Jun 03:49 UTC
Core cask tap HEAD: cb9b026407c215ca25358d5932c5738c7e49aa64
Core cask tap last commit: 5 minutes ago
Core cask tap JSON: 17 Jun 03:49 UTC
HOMEBREW_PREFIX: /usr/local
HOMEBREW_CASK_OPTS: []
HOMEBREW_EDITOR: vi
HOMEBREW_MAKE_JOBS: 16
HOMEBREW_SORBET_RUNTIME: set
Homebrew Ruby: 3.3.3 => /usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/3.3.3/bin/ruby
CPU: 16-core 64-bit kabylake
Clang: 15.0.0 build 1500
Git: 2.39.3 => /Library/Developer/CommandLineTools/usr/bin/git
Curl: 8.4.0 => /usr/bin/curl
macOS: 14.4.1-x86_64
CLT: 15.3.0.0.1.1708646388
Xcode: 15.4

Output of brew tap

brewsci/base
coursier/formulas
grpc/grpc
heroku/brew
homebrew/bundle
homebrew/cask
homebrew/cask-fonts
homebrew/cask-versions
homebrew/core
homebrew/services
libsql/sqld
mongodb/brew
moritzsternemann/apple-fonts
teamookla/speedtest
tektoncd/tools
tilt-dev/tap
tursodatabase/tap
ubuntu/microk8s

[bevanjkay]

Please see #173201 (comment)