handle unassignment of role

internal/permissions/assignments.go

@@ -45,6 +45,29 @@ func (c *Client) AssignRole(ctx context.Context, roleID gidx.PrefixedID, memberI
 	return nil
 }
 
+func (c *Client) UnassignRole(ctx context.Context, roleID gidx.PrefixedID, memberID gidx.PrefixedID) error {
+	path := fmt.Sprintf("/api/v1/roles/%s/assignments", roleID.String())
+
+	body, err := encodeJSON(RoleAssign{
+		SubjectID: memberID.String(),
+	})
+	if err != nil {
+		return err
+	}
+
+	var response RoleAssignResponse
+
+	if _, err = c.DoRequest(ctx, http.MethodDelete, path, body, &response); err != nil {
+		return err
+	}
+
+	if !response.Success {
+		return ErrUnassignmentFailed
+	}
+
+	return nil
+}
+
 func (c *Client) ListRoleAssignments(ctx context.Context, roleID gidx.PrefixedID) ([]gidx.PrefixedID, error) {
 	path := fmt.Sprintf("/api/v1/roles/%s/assignments", roleID.String())