vendor: lineage: Upgrade to LineageOS 15.1

 * Update backuptool versions
 * Update text references
 * Set version minor to 1

Change-Id: I30eea1f1cb01e2165311364cc62b589669bb1290
diff --git a/config/common.mk b/config/common.mk
index 05a970c..841ad78 100644
--- a/config/common.mk
+++ b/config/common.mk
@@ -236,7 +236,7 @@
 DEVICE_PACKAGE_OVERLAYS += vendor/lineage/overlay/common
 
 PRODUCT_VERSION_MAJOR = 15
-PRODUCT_VERSION_MINOR = 0
+PRODUCT_VERSION_MINOR = 1
 PRODUCT_VERSION_MAINTENANCE := 0
 
 ifeq ($(TARGET_VENDOR_SHOW_MAINTENANCE_VERSION),true)