change lookback mins to 7 days (#853)

Co-authored-by: Bryan Burkholder <[email protected]>

astra/src/main/java/com/slack/astra/zipkinApi/ZipkinService.java

@@ -132,7 +132,7 @@ protected static long convertToMicroSeconds(Instant instant) {
   }
 
   private static final Logger LOG = LoggerFactory.getLogger(ZipkinService.class);
-  private static long LOOKBACK_MINS = 60 * 24;
+  private static long LOOKBACK_MINS = 60 * 24 * 7;
 
   private static final int MAX_SPANS = 20_000;