Set-Cookie names must not be lowercase

This changeset aligns the "Set-Cookie" propertie names with the
RFC6265 in the sense that according to syntax (see
https://datatracker.ietf.org/doc/html/draft-ietf-httpbis-rfc6265bis#section-4.1.1)
all the names must uppercase the first character.

Most browsers are lax in how they interpret the cookies so the
old behavior should not cause any issues, but its better to
align with the spec.

servicetalk-http-api/src/main/java/io/servicetalk/http/api/DefaultHttpSetCookie.java

@@ -34,13 +34,13 @@
  * Default implementation of {@link HttpSetCookie}.
  */
 public final class DefaultHttpSetCookie implements HttpSetCookie {
-    private static final String ENCODED_LABEL_DOMAIN = "; domain=";
-    private static final String ENCODED_LABEL_PATH = "; path=";
-    private static final String ENCODED_LABEL_EXPIRES = "; expires=";
-    private static final String ENCODED_LABEL_MAX_AGE = "; max-age=";
-    private static final String ENCODED_LABEL_HTTP_ONLY = "; httponly";
-    private static final String ENCODED_LABEL_SECURE = "; secure";
-    private static final String ENCODED_LABEL_SAMESITE = "; samesite=";
+    private static final String ENCODED_LABEL_DOMAIN = "; Domain=";
+    private static final String ENCODED_LABEL_PATH = "; Path=";
+    private static final String ENCODED_LABEL_EXPIRES = "; Expires=";
+    private static final String ENCODED_LABEL_MAX_AGE = "; Max-Age=";
+    private static final String ENCODED_LABEL_HTTP_ONLY = "; HttpOnly";
+    private static final String ENCODED_LABEL_SECURE = "; Secure";
+    private static final String ENCODED_LABEL_SAMESITE = "; SameSite=";
 
     private final CharSequence name;
     private final CharSequence value;

servicetalk-http-api/src/test/java/io/servicetalk/http/api/DefaultHttpSetCookieTest.java

@@ -21,6 +21,7 @@
 import static io.servicetalk.http.api.HttpSetCookie.SameSite.Lax;
 import static io.servicetalk.http.api.HttpSetCookie.SameSite.None;
 import static org.hamcrest.MatcherAssert.assertThat;
+import static org.hamcrest.Matchers.containsString;
 import static org.hamcrest.Matchers.is;
 import static org.hamcrest.Matchers.not;
 
@@ -81,4 +82,17 @@ void testNotEqual() {
                 is(not(new DefaultHttpSetCookie("foo", "bar", "/path", "docs.servicetalk.io",
                         null, 1L, None, true, false, true).hashCode())));
     }
+
+    @Test
+    void testUppercaseNames() {
+        String encoded = new DefaultHttpSetCookie("foo", "bar", "myPath", "myDomain", "10", 10L, Lax,
+                false, true, true).encoded().toString();
+        assertThat(encoded, containsString("Path=myPath"));
+        assertThat(encoded, containsString("Domain=myDomain"));
+        assertThat(encoded, containsString("Expires=10"));
+        assertThat(encoded, containsString("Max-Age=10"));
+        assertThat(encoded, containsString("SameSite=Lax"));
+        assertThat(encoded, containsString("HttpOnly"));
+        assertThat(encoded, containsString("Secure"));
+    }
 }