Make since-perl optional

Author: atoomic

README.md

@@ -37,7 +37,7 @@ jobs:
         id: action
         uses: perl-actions/perl-versions@v1
         with:
-          since-perl: "v5.20"
+          since-perl: v5.20
 
   test:
     needs:
@@ -71,7 +71,7 @@ jobs:
   perl-versions:
     uses: perl-actions/perl-versions@v1
     with:
-      since-perl: 5.10
+      since-perl: 5.14
 
   test:
     needs:

action.yml

@@ -4,7 +4,7 @@ inputs:
   since-perl:
     description: "List all Perl versions since this (including this). Example: 5.10"
     type: string
-    required: true
+    default: "5.14"
   with-devel:
     description: "Whether to include also 'devel' Perl"
     type: boolean