docs: update sprig links to our domain

Author: andreynering

website/src/blog/any-variables.md

@@ -144,5 +144,5 @@ We're looking for feedback on a couple of different proposals, so please give
 them a go and let us know what you think. :pray:
 
 [v3.37.0]: https://github.com/go-task/task/releases/tag/v3.37.0
-[slim-sprig-math]: https://go-task.github.io/slim-sprig/math.html
-[slim-sprig-list]: https://go-task.github.io/slim-sprig/lists.html
+[slim-sprig-math]: https://sprig.taskfile.dev/math.html
+[slim-sprig-list]: https://sprig.taskfile.dev/lists.html

website/src/docs/guide.md

@@ -467,7 +467,7 @@ includes:
 Vars declared in the included Taskfile have preference over the variables in the
 including Taskfile! If you want a variable in an included Taskfile to be
 overridable, use the
-[default function](https://go-task.github.io/slim-sprig/defaults.html):
+[default function](https://sprig.taskfile.dev/defaults.html):
 <span v-pre>`MY_VAR: '{{.MY_VAR | default "my-default-value"}}'`</span>.
 
 :::