implementation: keyrings MUST fail if they refuse to take action #226
Description
Following up from #224, all keyrings MUST fail if they are unable or unwilling to write or satisfy decryption contracts.
- Java keyrings MUST fail if they refuse to take action aws/aws-encryption-sdk-java#216
- Javascript keyrings MUST fail if they refuse to take action aws/aws-encryption-sdk-javascript#416
- Python keyrings MUST fail if they refuse to take action aws/aws-encryption-sdk-python#294
- C keyrings MUST fail if they refuse to take action aws/aws-encryption-sdk-c#583