Fix the john6-voiture challenge for use on RPI4
juniorctf
does not install on RPI4 because the john
package does not exist in alpine linux 3.7 for architecture aarch64. However it does exist in the latest alpine release 3.11
This PR upgrades the alpine version used in the john6-challenge to make it works on RPI4. Note, that in this version, there is no typo in the program unshadow
.