ForbiddenByRbac when using azure key vault backend with version 3.8+

[andrey-gava]

Hi!
We successfully using sops 3.7.3 with azure key vault as backend.
But when we try to use same flow with 3.8+ version it fails with ForbiddenByRbac error.
I tried both login type - az login and service principle credentials. Both fails.
I have next roles permission to resource: [Key Vault Crypto Officer, Key Vault Crypto User]

Something changed in how sops authenticate with azure resources?

./sops-v3.8.1.linux.amd64 ~/git/environments/aks-saas/secrets.yaml

Failed to get the data key required to decrypt the SOPS file.

Group 0: FAILED
  https://*******.vault.azure.net/keys/sops-aks-saas-key/*********************: FAILED
    - | failed to decrypt sops data key with Azure Key Vault key
      | 'https://*******.vault.azure.net/keys/sops-aks-saas-key/*********************':
      | POST
      | https://*******.vault.azure.net/keys/sops-aks-saas-key/*********************/decrypt
      | --------------------------------------------------------------------------------
      | RESPONSE 403: 403 Forbidden
      | ERROR CODE: Forbidden
      | --------------------------------------------------------------------------------
      | {
      |   "error": {
      |     "code": "Forbidden",
      |     "message": "Caller is not authorized to perform action
      | on resource.\r\nIf role assignments, deny assignments or
      | role definitions were changed recently, please observe
      | propagation time.\r\nCaller:
      | appid=********************;oid=*********************;iss=https://sts.windows.net/**************/\r\nAction:
      | 'Microsoft.KeyVault/vaults/keys/decrypt/action'\r\nResource:
      | '/subscriptions/************************/resourcegroups/****/providers/microsoft.keyvault/vaults/*******/keys/sops-aks-saas-key'\r\nAssignment:
      | (not found)\r\nDenyAssignmentId: null\r\nDecisionReason:
      | null \r\nVault: *******;location=********\r\n",
      |     "innererror": {
      |       "code": "ForbiddenByRbac"
      |     }
      |   }
      | }
      | --------------------------------------------------------------------------------