Migrate to the regex library away from std/nre, as the libpcre version that std/nre depends on is being deprecated in many distros.

tests/test1.nim

@@ -1 +1,29 @@
-doAssert(1 + 1 == 2)
+import std/[options, tables, times, unittest]
+
+import pit/libpit
+
+suite "regex-backed issue behavior":
+  test "summary and full-text filters are case-insensitive":
+    let issue = Issue(
+      summary: "Fix the Widget",
+      details: "Failure happens in the renderer",
+      properties: newTable[string, string](),
+      tags: @[])
+
+    check @[issue].filter(summaryMatchFilter("widget")).len == 1
+    check @[issue].filter(summaryMatchFilter("missing")).len == 0
+    check @[issue].filter(fullMatchFilter("RENDERER")).len == 1
+
+  test "recurrence values parse captures":
+    let issue = Issue(
+      summary: "repeating",
+      properties: newTable[string, string](),
+      tags: @[])
+
+    issue["recurrence"] = "after 2 weeks, abc123"
+
+    let recurrence = issue.getRecurrence()
+    check recurrence.isSome
+    check recurrence.get.isFromCompletion
+    check recurrence.get.interval == weeks(2)
+    check recurrence.get.cloneId == some("abc123")