database: increase size limit of packages to 1.2 MB

By now, there are some large packages whose documentation exceeds
the current size limit of 800 KB. Increase the limit by 1.5x to
accomodate such packages.

Fixes #635

Change-Id: Ie846366d2aea6a58f3cca3080c99fc0124995e5d
Reviewed-on: https://go-review.googlesource.com/c/gddo/+/190398
Reviewed-by: Tuo Shan <shantuo@google.com>

Author: dmitshur

database/database.go

@@ -261,7 +261,7 @@ func (db *Database) Put(ctx context.Context, pdoc *doc.Package, nextCrawl time.T
 	gobBytes := snappy.Encode(nil, gobBuf.Bytes())
 
 	// Truncate large documents.
-	if len(gobBytes) > 800000 {
+	if len(gobBytes) > 1200000 {
 		pdocNew := *pdoc
 		pdoc = &pdocNew
 		pdoc.Truncated = true