CI: formal check: use shared workflow in actions-shared-workflows

[BKPepe]

Lets switch to shared workflow in actions-shared-workflows instead of having this separate file here. It will track and use the latest changes to avoid being outdated.

[BKPepe]

Even my changes are not related to the failing checks, but cjdns is not compiled. It fails with this output:

2025-06-16T18:30:11.1037401Z 
2025-06-16T18:30:11.1038142Z �[01m�[Kcc1:�[m�[K �[01;36m�[Knote: �[m�[Ksomeone does not honour COPTS correctly, passed 16 times
2025-06-16T18:30:11.1039105Z �[01m�[Ktest/testcjdroute.c:�[m�[K In function '�[01m�[KinitFuzzTests�[m�[K':
2025-06-16T18:30:11.1040844Z �[01m�[Ktest/testcjdroute.c:116:57:�[m�[K �[01;31m�[Kerror: �[m�[K'�[01m�[KAllocator__calloc�[m�[K' sizes specified with '�[01m�[Ksizeof�[m�[K' in the earlier argument and not in the later argument [�[01;31m�[K-Werror=calloc-transposed-args�[m�[K]
2025-06-16T18:30:11.1042622Z   116 |     void** contexts = Allocator_calloc(alloc, sizeof(cha�[01;31m�[Kr*),�[m�[K FUZZ_TEST_COUNT);
2025-06-16T18:30:11.1043460Z       |                                                         �[01;31m�[K^~~~�[m�[K
2025-06-16T18:30:11.1044544Z �[01m�[Ktest/testcjdroute.c:116:57:�[m�[K �[01;36m�[Knote: �[m�[Kearlier argument should specify number of elements, later size of each element
2025-06-16T18:30:11.1046267Z cc1: all warnings being treated as errors
2025-06-16T18:30:11.1046602Z 
2025-06-16T18:30:11.1047191Z     at error (/builder/build_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/cjdns-cjdns-v21.1/node_build/builder.js:104:15)
2025-06-16T18:30:11.1048452Z     at /builder/build_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/cjdns-cjdns-v21.1/node_build/builder.js:185:29
2025-06-16T18:30:11.1049654Z     at /builder/build_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/cjdns-cjdns-v21.1/node_build/builder.js:150:17
2025-06-16T18:30:11.1051100Z     at ChildProcess.<anonymous> (/builder/build_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/cjdns-cjdns-v21.1/node_modules/saferphore/index.js:22:34)
2025-06-16T18:30:11.1052121Z     at emitTwo (events.js:106:13)
2025-06-16T18:30:11.1052540Z     at ChildProcess.emit (events.js:191:7)
2025-06-16T18:30:11.1053005Z     at maybeClose (internal/child_process.js:877:16)
2025-06-16T18:30:11.1053663Z     at Process.ChildProcess._handle.onexit (internal/child_process.js:226:5)
2025-06-16T18:30:11.1163828Z make[2]: *** [Makefile:154: /builder/build_dir/target-arm_cortex-a15+neon-vfpv4_musl_eabi/cjdns-cjdns-v21.1/.built] Error 1
2025-06-16T18:30:11.1169403Z make[2]: Leaving directory '/feed/cjdns'
2025-06-16T18:30:11.1170238Z time: package/feeds/packages_ci/cjdns/compile#25.94#11.91#15.68
2025-06-16T18:30:11.1182094Z     ERROR: package/feeds/packages_ci/cjdns failed to build.
2025-06-16T18:30:11.1193459Z make[1]: *** [package/Makefile:183: package/feeds/packages_ci/cjdns/compile] Error 1
2025-06-16T18:30:11.1194183Z make[1]: Leaving directory '/builder'
2025-06-16T18:30:11.1203933Z make: *** [/builder/include/toplevel.mk:226: package/cjdns/compile] Error 2
2025-06-16T18:30:11.1213133Z ##[group]  make package/index

[PolynomialDivision]

Thanks.