checkapk: handle + in pkgname

the pkgname is passed to awk, and + matches in regex, so it fails to
match the actual package name.

closes #10077

checkapk.in

@@ -75,7 +75,7 @@ for i in $pkgname $subpackages; do
 	# For our local repo (newsize) apk info might return multiple packages, e.g. if different
 	# version of the package where build previously. Filter out this specific pkgver using awk.
 	newsize=$(apk info --repositories-file /dev/null --repository "$REPODEST"/$repo --size $_pkgname | \
-		awk "/^$pkg/ { found = 1 } /^[0-9]+/ { if (found) { print \$0; exit } }")
+		awk "/^${pkg//+/\\+}/ { found = 1 } /^[0-9]+/ { if (found) { print \$0; exit } }")
 	oldsize=$(apk info --repositories-file $tmpdir/repositories --size $_pkgname | awk '/^[0-9]+/ { print $0 }' | head -1)
 
 	if [ "$oldsize" = "$newsize" ]; then