Added example of having age recipients in .sops.yaml

Fixed formatting for example of multiple age keys in .sops.yaml

Added example of using updatekeys with age

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Converted from getsops/sops@59440d9

Co-authored-by: Carsten Skov <carsten@simcax.dk>
Signed-off-by: Carsten Skov <carsten@simcax.dk>
Signed-off-by: Felix Fontein <felix@fontein.de>

Author: felixfontein

content/en/docs/_index.md

@@ -234,6 +234,28 @@ decrypt the data.
 
 Encrypting with SSH keys via age is not yet supported by SOPS.
 
+A list of age recipients can be added to the `.sops.yaml`:
+
+``` yaml
+creation_rules:
+    - age: >-
+        age1s3cqcks5genc6ru8chl0hkkd04zmxvczsvdxq99ekffe4gmvjpzsedk23c,
+        age1qe5lxzzeppw5k79vxn3872272sgy224g2nzqlzy3uljs84say3yqgvd0sw
+```
+
+It is also possible to use `updatekeys`, when adding or removing age recipients. For example:
+
+``` sh
+$ sops updatekeys secret.enc.yaml
+2022/02/09 16:32:02 Syncing keys for file /iac/solution1/secret.enc.yaml
+The following changes will be made to the file's groups:
+Group 1
+    age1s3cqcks5genc6ru8chl0hkkd04zmxvczsvdxq99ekffe4gmvjpzsedk23c
++++ age1qe5lxzzeppw5k79vxn3872272sgy224g2nzqlzy3uljs84say3yqgvd0sw
+Is this okay? (y/n):y
+2022/02/09 16:32:04 File /iac/solution1/secret.enc.yaml synced with new keys
+```
+
 ## Encrypting using GCP KMS
 
 GCP KMS uses [Application Default