fix(cli): use lowercase version option

tests/unit/cli.bats

@@ -24,12 +24,14 @@ setup() { common_setup; }
 	assert_line 'usage: skeptical-updater [options] [command]'
 }
 
-@test "--version and -V print the version" {
+@test "--version and -v print the version" {
 	run skup --version
 	assert_success
-	assert_output 'skeptical-updater 0.1.0'
-	run skup -V
-	assert_output 'skeptical-updater 0.1.0'
+	assert_output --regexp '^skeptical-updater [0-9]+\.[0-9]+\.[0-9]+(\+(alpha|beta|rc)[.-]?[0-9]+)?$'
+	local version=$output
+	run skup -v
+	assert_success
+	assert_output "$version"
 }
 
 @test "an unknown option is a usage error (exit 1)" {