Make feature name required for Experimental (#3859)

We have discussed this in community meetings and
Slack, and have informally agreed that
a conformance Feature Name must be set for a
GEP to graduate to Experimental.

This commit adds changes to the GEP process page and
the GEP template to make this official.

Signed-off-by: Nick Young <[email protected]>

Author: youngnick

geps/gep-696/index.md

@@ -47,6 +47,8 @@ Every feature should:
 3. Not exceed 128 characters.
 4. Contain only letters and numbers
 
+GEPs cannot move to Experimental without a Feature Name.
+
 ### Conformance tests 
 
 Conformance tests file names should try to follow the `pascal-case-name.go` format.

geps/overview.md

@@ -151,6 +151,8 @@ use the `experimental` Golang build tag to denote experimental functionality.
 Some other requirements must be met before marking a GEP `Experimental`:
 
 - the graduation criteria to reach `Standard` MUST be filled out
+- the GEP must have at least one Feature Name for features described inside that
+  will need to be tested by conformance tests.
 - a proposed probationary period (see next section) must be included in the GEP
   and approved by maintainers.