Between yacl 3.0.0 and 3.2.0 your dependency structure changed so that a simple

modImplementation "dev.isxander.yacl:yet-another-config-lib-fabric:3.2.0+1.20"

doesn't work.
Gradle fails to resolve your transitive dependencies since they are hosted on unknown repositories.

• com.twelvemonkeys.imageio requires https://oss.sonatype.org/content/repositories/snapshots
• org.quiltmc.parsers requires https://maven.quiltmc.org/repository/release

A workaround that I'm currently using is to exclude these dependencies.

modImplementation("dev.isxander.yacl:yet-another-config-lib-fabric:<version>") {
    exclude(group: "org.quiltmc.parsers")
    exclude(group: "com.twelvemonkeys.common")
    exclude(group: "com.twelvemonkeys.imageio")
}

same for 3.2.1

I now mirror quilt parsers!

It is true that you need these repositories for YACL to work. The next version the ImageIO lib is back on maven central, but until I start mirroring quilt parsers I'll just need to reflect this in the documentation.