Ruby

[rubygems/rubygems] Set $0 to exe when running gem exec to fix name in CLI output

The $0 value is used in many CLI libraries to determine the name of the
application, when displaying help and error messages.

Without setting this value, it defaults to gem which can be confusing.

Before:

$ gem exec kamal help
Commands:
  gem accessory           # Manage accessories (db/redis/search)
  gem app                 # Manage application
  gem audit               # Show audit log from servers
  gem build               # Build application image
  gem config              # Show combined config (including secrets!)
  gem deploy              # Deploy app to servers
  gem details             # Show details about all containers
  gem docs [SECTION]      # Show Kamal configuration documentation
  gem help [COMMAND]      # Describe available commands or one specific command
  gem init                # Create config stub in config/deploy.yml and secrets stub in .kamal
  gem lock                # Manage the deploy lock
  gem proxy               # Manage kamal-proxy
  gem prune               # Prune old application images and containers
  gem redeploy            # Deploy app to servers without bootstrapping servers, starting kamal-proxy, pruning, and registry login
  gem registry            # Login and -out of the image registry
  gem remove              # Remove kamal-proxy, app, accessories, and registry session from servers
  gem rollback [VERSION]  # Rollback app to VERSION
  gem secrets             # Helpers for extracting secrets
  gem server              # Bootstrap servers with curl and Docker
  gem setup               # Setup all accessories, push the env, and deploy app to servers
  gem upgrade             # Upgrade from Kamal 1.x to 2.0
  gem version             # Show Kamal version

After:

$ gem exec kamal help
Commands:
  kamal accessory           # Manage accessories (db/redis/search)
  kamal app                 # Manage application
  kamal audit               # Show audit log from servers
  kamal build               # Build application image
  kamal config              # Show combined config (including secrets!)
  kamal deploy              # Deploy app to servers
  kamal details             # Show details about all containers
  kamal docs [SECTION]      # Show Kamal configuration documentation
  kamal help [COMMAND]      # Describe available commands or one specific command
  kamal init                # Create config stub in config/deploy.yml and secrets stub in .kamal
  kamal lock                # Manage the deploy lock
  kamal proxy               # Manage kamal-proxy
  kamal prune               # Prune old application images and containers
  kamal redeploy            # Deploy app to servers without bootstrapping servers, starting kamal-proxy, pruning, and registry login
  kamal registry            # Login and -out of the image registry
  kamal remove              # Remove kamal-proxy, app, accessories, and registry session from servers
  kamal rollback [VERSION]  # Rollback app to VERSION
  kamal secrets             # Helpers for extracting secrets
  kamal server              # Bootstrap servers with curl and Docker
  kamal setup               # Setup all accessories, push the env, and deploy app to servers
  kamal upgrade             # Upgrade from Kamal 1.x to 2.0
  kamal version             # Show Kamal version

https://github.com/rubygems/rubygems/commit/4fd060b96d