Upcase cookie header name

Since migrating to http4s we observed a flaw in cookie processing.
Previously, with akka the headers were uppercased. Http4s follows
RFC[1] related to header names more closely ignoring the case.
This had a result in missing cookie extractions in enrich that only
supports upper case Cookie header.

We are making enrich case-insensitive. Meanwhile, until the change
is migrated this is a workaround that will upcase cookie header.

1 -  https://www.rfc-editor.org/rfc/rfc7230#section-3.2

core/src/main/scala/com.snowplowanalytics.snowplow.collector.core/Service.scala

@@ -304,7 +304,10 @@ class Service[F[_]: Sync](
     request.headers.headers.flatMap { h =>
       h.name match {
         case ci"X-Forwarded-For" | ci"X-Real-Ip" | ci"Cookie" if spAnonymous.isDefined => None
-        case _ => Some(h.toString())
+        // FIXME: This is a temporary backport of old akka behaviour we will remove by
+        //        adapting enrich to support a CIString header names as per RFC7230#Section-3.2
+        case ci"Cookie" => Some(s"Cookie: ${h.value}")
+        case _          => Some(h.toString())
       }
     }
 

core/src/test/scala/com.snowplowanalytics.snowplow.collector.core/ServiceSpec.scala

@@ -288,6 +288,32 @@ class ServiceSpec extends Specification {
         ).asJava
       }
 
+      "sink event with Cookie header upcased" in {
+        val ProbeService(service, good, bad) = probeService()
+
+        val req = Request[IO](
+          method  = Method.POST,
+          headers = Headers(Header.Raw(CIString("cookie"), "name=value"))
+        )
+        val r = service
+          .cookie(
+            body          = IO.pure(Some("b")),
+            path          = "p",
+            request       = req,
+            pixelExpected = false,
+            contentType   = Some("image/gif")
+          )
+          .unsafeRunSync()
+
+        r.status mustEqual Status.Ok
+        good.storedRawEvents must have size 1
+        bad.storedRawEvents must have size 0
+
+        val e = emptyCollectorPayload
+        deserializer.deserialize(e, good.storedRawEvents.head)
+        e.headers.asScala must contain("Cookie: name=value")
+      }
+
       "return necessary cache control headers and respond with pixel when pixelExpected is true" in {
         val r = service
           .cookie(