devel/srell: Update 2026.05 => 2026.07

• Add hint to portscout(1) to help it discover new upstream versions

by pointing it to exact site:URL [1] with download directory listing,
as just generic one [0] strangely returns HTTP 403 error.

• Limit PORTSCOUT versions by following strict upstream YYYY.MM scheme.

[0] https://www.akenotsuki.com/misc/srell/releases/
[1] https://www.akenotsuki.com/misc/srell/releases/?C=M;O=D