Add inactivityThreshold to repo-specific-configuration.md

Author: fthomas

docs/repo-specific-configuration.md

@@ -201,6 +201,10 @@ reviewers = [ "username1", "username2" ]
 # If true, Scala Steward will sign off all commits (e.g. `git --signoff`).
 # Default: false
 signoffCommits = true
+
+# Repos whose last commit is older than this threshold are considered
+# inactive and are ignored.
+inactivityThreshold = "90 days"
 ```
 
 The version information given in the patterns above can be in two formats:

modules/core/src/main/scala/org/scalasteward/core/util/dateTime.scala

@@ -36,7 +36,7 @@ object dateTime {
     Decoder[String].emap(parseFiniteDuration(_).leftMap(_.getMessage))
 
   implicit val finiteDurationEncoder: Encoder[FiniteDuration] =
-    Encoder[String].contramap(renderFiniteDuration)
+    Encoder[String].contramap(_.toString)
 
   def showDuration(d: FiniteDuration): String = {
     def symbol(unit: TimeUnit): String =

modules/docs/mdoc/repo-specific-configuration.md

@@ -206,6 +206,10 @@ reviewers = [ "username1", "username2" ]
 # If true, Scala Steward will sign off all commits (e.g. `git --signoff`).
 # Default: false
 signoffCommits = true
+
+# Repos whose last commit is older than this threshold are considered
+# inactive and are ignored.
+inactivityThreshold = "90 days"
 """
 
 DocChecker.verifyParsedEqualsEncoded[RepoConfig](input)