fix: use correct securityContext for Alpine based helm-repository Pod

[dkoshkin]

What problem does this PR solve?:
User 65532 is the default UID in distroless based images, but in Alpine it's a different user and group.

Which issue(s) this PR fixes:
Fixes #

How Has This Been Tested?:

Special notes for your reviewer:

[dkoshkin]

This is the guest user in the Alpine image

➜  ~ docker run -it alpine:latest
/ # users
/bin/sh: users: not found
/ # getent passwd
root:x:0:0:root:/root:/bin/sh
bin:x:1:1:bin:/bin:/sbin/nologin
daemon:x:2:2:daemon:/sbin:/sbin/nologin
lp:x:4:7:lp:/var/spool/lpd:/sbin/nologin
sync:x:5:0:sync:/sbin:/bin/sync
shutdown:x:6:0:shutdown:/sbin:/sbin/shutdown
halt:x:7:0:halt:/sbin:/sbin/halt
mail:x:8:12:mail:/var/mail:/sbin/nologin
news:x:9:13:news:/usr/lib/news:/sbin/nologin
uucp:x:10:14:uucp:/var/spool/uucppublic:/sbin/nologin
cron:x:16:16:cron:/var/spool/cron:/sbin/nologin
ftp:x:21:21::/var/lib/ftp:/sbin/nologin
sshd:x:22:22:sshd:/dev/null:/sbin/nologin
games:x:35:35:games:/usr/games:/sbin/nologin
ntp:x:123:123:NTP:/var/empty:/sbin/nologin
guest:x:405:100:guest:/dev/null:/sbin/nologin
nobody:x:65534:65534:nobody:/:/sbin/nologin

docker run -it -u 405  alpine:latest
/ $ whoami
guest
/ $ id
uid=405(guest) gid=100(users) groups=100(users)

[dkoshkin]

Maybe we actually want the nobody user?