Small tweaks following release

Author: essen

doc/src/guide/book.asciidoc

@@ -79,7 +79,7 @@ include::security_checklist.asciidoc[Security checklist]
 
 = Additional information
 
-include::migrating_from_2.16.asciidoc[Changes since Cowboy 2.16]
+include::migrating_from_2.16.asciidoc[Migrating from Cowboy 2.16 to 2.17]
 
 include::migrating_from_2.15.asciidoc[Migrating from Cowboy 2.15 to 2.16]
 

rebar.config

@@ -1,4 +1,4 @@
 {deps, [
-{cowlib,".*",{git,"https://github.com/ninenines/cowlib",{ref,"2.18.0"}}},{ranch,".*",{git,"https://github.com/ninenines/ranch",{tag,"1.8.1"}}}
+{cowlib,".*",{git,"https://github.com/ninenines/cowlib",{tag,"2.18.0"}}},{ranch,".*",{git,"https://github.com/ninenines/ranch",{tag,"1.8.1"}}}
 ]}.
 {erl_opts, [debug_info,warn_export_vars,warn_shadow_vars,warn_obsolete_guard,warn_missing_spec,warn_untyped_record]}.