Add LTS to SPEC 0

Author: jarrodmillman

spec-0000/index.md

@@ -42,6 +42,14 @@ For instance, if a newer minimum version of a core package is needed by a projec
 which is not backported to older versions.
 {{< /admonition >}}
 
+{{< admonition note >}}
+Certain projects (e.g., projects that have more developer releases) may wish to provide long-term support (LTS) of an additional year.
+
+Specifically, for projects wishing to provide LTS we recommend that:
+1. Support for Python versions be dropped **4 years** after the next version of Python is released.
+2. Support for core package dependencies be dropped **3 years** after the next version of the package is released.
+{{< /admonition >}}
+
 ### Core Project Endorsement
 
 <!--