Upgrade openpgpjs to 6.2.1

[sosnovsky]

After upgrading openpgpjs to 6.2.1, build fails with error:

resolve-modules ERROR: Relative import should start with a dot in build/generic-extension-wip/lib/openpgp.js:
--
import { p256 } from '@noble/curves/nist.js';
--

❌ Error during build: Error: Command failed: node .../flowcrypt-browser/build/tooling/resolve-modules --project ./tsconfig.json
    at genericNodeError (node:internal/errors:985:15)
    at wrappedFn (node:internal/errors:539:14)
    at checkExecSyncError (node:child_process:925:11)
    at execSync (node:child_process:997:15)
    at runCmd (.../flowcrypt-browser/scripts/build.js:21:3)
    at main (.../flowcrypt-browser/scripts/build.js:149:5) {
  status: 1,
  signal: null,
  output: [ null, null, null ],
  pid: 43406,
  stdout: null,
  stderr: null
}