Replace hardcoded version with Version.java value

Bats version check tests now use a bash script for parsing
the value from the Bisq class file, and these test cases
no longer need to be manually updated.

apitest/scripts/mainnet-test.sh

@@ -16,6 +16,8 @@
 #
 #     ./cli/test.sh
 
+# load 'mainnet-test-helper'
+
 @test "test unsupported method error" {
   run ./bisq-cli --password=xyz bogus
   [ "$status" -eq 1 ]
@@ -45,17 +47,19 @@
 }
 
 @test "test getversion call with quoted password" {
+  load 'version-parser'
   run ./bisq-cli --password="xyz" getversion
   [ "$status" -eq 0 ]
   echo "actual output:  $output" >&2
-  [ "$output" = "1.3.9" ]
+  [ "$output" = "$CURRENT_VERSION" ]
 }
 
 @test "test getversion" {
+  load 'version-parser'
   run ./bisq-cli --password=xyz getversion
   [ "$status" -eq 0 ]
   echo "actual output:  $output" >&2
-  [ "$output" = "1.3.9" ]
+  [ "$output" = "$CURRENT_VERSION" ]
 }
 
 @test "test setwalletpassword \"a b c\"" {

apitest/scripts/version-parser.bash

@@ -0,0 +1,5 @@
+#!/bin/bash
+
+# Bats helper script for parsing current version from Version.java.
+
+export CURRENT_VERSION=$(grep "String VERSION =" common/src/main/java/bisq/common/app/Version.java | sed 's/[^0-9.]*//g')