devel/py-sysctl: Update to 0.3.0

[freqlabs]

Summary

Bring py-sysctl to 0.3.0, which features the following changes:

• .value now lazy-loaded on first access to avoid the overhead of getting unused values
• .description field added, also lazy-loaded on first access to minimize overhead
• Support for CTL_SYSCTL_NEXTNOSKIP to include sysctls marked with CTLFLAG_SKIP once D26560 lands