Fix: TypeScript Type Error when exactOptionalPropertyTypes is enabled

[taranda]

This PR should resolve issue #92.

Right now, when exactOptionalPropertyTypes: true, running npx tsc results in the following error:

node_modules/node-webcrypto-p11/build/index.d.ts:156:15 - error TS2420: Class 'CryptoKey$1<T>' incorrectly implements interface 'AlwaysAuthenticateParams'.
  Types of property 'alwaysAuthenticate' are incompatible.
    Type 'boolean | undefined' is not assignable to type 'boolean'.
      Type 'undefined' is not assignable to type 'boolean'.

156 declare class CryptoKey$1<T extends Pkcs11KeyAlgorithm = Pkcs11KeyAlgorithm> extends core.CryptoKey implements AlwaysAuthenticateParams {
                  ~~~~~~~~~~~


Found 1 error in node_modules/node-webcrypto-p11/build/index.d.ts:156

This PR should fix that.

[fenichelar]

@microshine sorry to ping you but would it be possible for this to be reviewed?