Typo: 'exechangeRate' should be 'exchangeRate'

[hwhsu1231]

Additional context

I noticed a typo in a variable name within the project.

The variable exechangeRate/SPONSORKIT_AFDIAN_EXECHANGERATE/AFDIAN_EXECHANGERATE appear to be a misspelling of exchangeRate/SPONSORKIT_AFDIAN_EXCHANGERATE/AFDIAN_EXCHANGERATE, which represent "Exchange Rate".

sponsorkit/src/configs/env.ts

Line 34 in 71468ab

exechangeRate: Number.parseFloat(process.env.SPONSORKIT_AFDIAN_EXECHANGERATE || process.env.AFDIAN_EXECHANGERATE || '0') || undefined,

Since this sponsorkit package is widely used, I opted not to submit a PR directly to avoid potentially disrupting downstream projects that depend on it. I leave it to the authors to decide whether to address this issue.

[sxzz]

Let's fix it by introducing a new option and marking the old one as deprecated.