feat(SlashCommands): add attachment option

[amitojsingh366]

Please describe the changes this PR makes and why it should be merged: This PR adds the ability to add an attachment option to slash commands

• [x] make addAttachmentOption
• [x] make SlashCommandAttachmentOption
• [x] add tests for SlashCommandAttachmentOption
• [ ] wait for https://github.com/discord/discord-api-docs/pull/4253 to be merged
• [ ] wait for https://github.com/discordjs/discord-api-types/pull/272 to be merged

Status and versioning classification: This PR relies on https://github.com/discordjs/discord-api-types/pull/272 and https://github.com/discord/discord-api-docs/pull/4253

NOTE: this is my first time contributing to this project so if anything is wrong please do tell me

[codecov-commenter]

Codecov Report

Merging #65 (ebfb69d) into main (0263f00) will not change coverage. The diff coverage is 100.00%.

@@            Coverage Diff            @@
##              main       #65   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           21        22    +1     
  Lines          276       279    +3     
  Branches        37        37           
=========================================
+ Hits           276       279    +3     

Impacted Files	Coverage Δ
...nteractions/slashCommands/mixins/CommandOptions.ts	100.00% <100.00%> (ø)
...c/interactions/slashCommands/options/attachment.ts	100.00% <100.00%> (ø)

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[amitojsingh366]

the workflow will error on this PR until https://github.com/discordjs/discord-api-types/pull/272 is merged