update readme

Author: batmac

README.md

@@ -35,10 +35,16 @@ $ cat -m zstd LICENSE | cat -m base64
 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
 ```
 
+## docker image
+an image is available, for instance:
+```
+kubectl run -i --tty ccat --image=batmac/ccat -- /bin/sh
+```
+
 ## help
 
 ```
-version >v0.9.6+dev [libcurl,crappy], commit 56c5b5d3f8f44cd962935cdaaa102bb75b4782c2, built at 2022-06-21@00:01:12 by build.sh
+version >v0.9.6+dev [libcurl,crappy], commit b982b36f8b6b601956caf784096d5aa56ce6a15c, built at 2022-06-22@00:07:53 by build.sh (go1.18.3)
   -t, --tokens string      comma-separated list of tokens
   -i, --ignore-case        tokens given with -t are case-insensitive
   -o, --only               don't display lines without at least one token