The issue you're encountering is due to the libspine_godot.ios.template_release being compiled with an iOS SDK version that is higher than the minimum OS version specified in your project's Info.plist. The library was compiled with iOS SDK 17.5, and it seems that the minimum iOS version was not set to 12.0 as required. To resolve this, you would need to recompile the library with the correct minimum iOS version setting. This involves modifying the build configuration to set miphoneos-version-min=12.0 in the SConstruct file or equivalent build script. Unfortunately, I cannot directly fix this for you, but you can follow the steps to compile the Godot editor and export templates from source as described in the spine-godot Runtime Documentation.

I've opened an issue here. EsotericSoftware/spine-runtimes2861

I have tried to figure out why the ios_min_version parameter isn't interpreted correctly by Scons, but couldn't find a fix. I've contacted the Godot folks for input on the matter.

Found a way by directly passing respective compiler/linker flags to the build. You can grab the latest extension binaries from https://esotericsoftware.com/spine-godot once this build completes successfully:
EsotericSoftware/spine-runtimesactions/runs/15209797741

Thanks for reporting!