fix(ci): prevent unknown pathspec error for custom base ref

[matejchalk]

The git checkout command errors for custom target refs (shallow fetch) specified by branch/tag name, so the commit SHA must be used.

[github-actions]

Code PushUp

🤨 Code PushUp report has both improvements and regressions – compared target commit 954fd22 with source commit b5bcdc9.

🕵️ See full comparison in Code PushUp portal 🔍

🏷️ Categories

🏷️ Category	⭐ Previous score	⭐ Current score	🔄 Score change
Performance	🟡 53	🔴 50
Code coverage	🟢 91	🟢 91	–
Security	🟡 75	🟡 75	–
Updates	🟡 77	🟡 77	–
Accessibility	🟢 92	🟢 92	–
Best Practices	🟢 100	🟢 100	–
SEO	🟡 61	🟡 61	–
Bug prevention	🟢 100	🟢 100	–
Code style	🟢 100	🟢 100	–
Documentation	🔴 23	🔴 23	–

👎 1 group regressed, 👍 1 audit improved, 👎 5 audits regressed, 10 audits changed without impacting score

🗃️ Groups

🔌 Plugin	🗃️ Group	⭐ Previous score	⭐ Current score	🔄 Score change
Lighthouse	Performance	🟡 53	🔴 50

17 other groups are unchanged.

🛡️ Audits

🔌 Plugin	🛡️ Audit	📏 Previous value	📏 Current value	🔄 Value change
Lighthouse	Initial server response time was short	🟥 Root document took 1,020 ms	🟩 Root document took 380 ms
Lighthouse	Speed Index	🟥 5.9 s	🟥 6.3 s
Lighthouse	First Contentful Paint	🟨 2.8 s	🟨 3.0 s
Lighthouse	Largest Contentful Paint	🟨 3.5 s	🟨 3.6 s
Lighthouse	Total Blocking Time	🟥 2,670 ms	🟥 3,890 ms
Lighthouse	Time to Interactive	🟥 12.6 s	🟥 12.8 s
Lighthouse	Avoids enormous network payloads	🟩 Total size was 1,825 KiB	🟩 Total size was 1,821 KiB
Lighthouse	Minimizes main-thread work	🟥 12.2 s	🟥 15.5 s
Lighthouse	Eliminate render-blocking resources	🟥 Potential savings of 1,010 ms	🟥 Potential savings of 150 ms
Lighthouse	Uses efficient cache policy on static assets	🟨 27 resources found	🟨 27 resources found
Lighthouse	Metrics	🟩 100%	🟩 100%
Lighthouse	Reduce unused CSS	🟥 Potential savings of 67 KiB	🟥 Potential savings of 67 KiB
Lighthouse	Max Potential First Input Delay	🟥 1,630 ms	🟥 1,660 ms
Lighthouse	JavaScript execution time	🟥 5.6 s	🟥 5.6 s
Lighthouse	Server Backend Latencies	🟩 110 ms	🟩 120 ms
Lighthouse	Network Round Trip Times	🟩 20 ms	🟩 20 ms

580 other audits are unchanged.