Pull request: all: improve prerelease version selection

Merge in DNS/adguard-home from fix-prereleases to master

Squashed commit of the following:

commit 34424e4
Merge: 02e832f 6f50a4c
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Thu Dec 24 17:46:43 2020 +0300

    Merge branch 'master' into fix-prereleases

commit 02e832f
Author: Ainar Garipov <A.Garipov@AdGuard.COM>
Date:   Wed Dec 23 17:27:37 2020 +0300

    all: improve prerelease version selection

Makefile

@@ -67,17 +67,20 @@ endif
 
 # Version properties
 COMMIT=$(shell git rev-parse --short HEAD)
+TAG_NAME=$(shell git describe --abbrev=0)
+PRERELEASE_VERSION=$(shell git describe --abbrev=0)
 # TODO(a.garipov): The cut call is a temporary solution to trim
 # prerelease versions.  See the comment in .goreleaser.yml.
-TAG_NAME=$(shell git describe --abbrev=0 | cut -c 1-8)
-RELEASE_VERSION=$(TAG_NAME)
+RELEASE_VERSION=$(shell git describe --abbrev=0 | cut -c 1-8)
 SNAPSHOT_VERSION=$(RELEASE_VERSION)-SNAPSHOT-$(COMMIT)
 
 # Set proper version
 VERSION=
 ifeq ($(TAG_NAME),$(shell git describe --abbrev=4))
 	ifeq ($(CHANNEL),edge)
 		VERSION=$(SNAPSHOT_VERSION)
+	else ifeq ($(CHANNEL),beta)
+		VERSION=$(PRERELEASE_VERSION)
 	else
 		VERSION=$(RELEASE_VERSION)
 	endif