Bump version to 0.72

Required on at least Android 5. Otherwise utilities that use dalvikvm may fail.

Issue happens on Nexus 7 with official 5.0/5.1 firmware and possibly other
AOSP ROMs.

app/build.gradle

@@ -14,8 +14,8 @@ android {
         applicationId "com.termux"
         minSdkVersion 21
         targetSdkVersion 28
-        versionCode 71
+        versionCode 72
-        versionName "0.71"
+        versionName "0.72"
     }
 
     buildTypes {

app/src/main/java/com/termux/app/BackgroundJob.java

@@ -103,6 +103,7 @@ public final class BackgroundJob {
         environment.add("TERM=xterm-256color");
         environment.add("HOME=" + TermuxService.HOME_PATH);
         environment.add("PREFIX=" + TermuxService.PREFIX_PATH);
+        environment.add("BOOTCLASSPATH" + System.getenv("BOOTCLASSPATH"));
         environment.add("ANDROID_ROOT=" + System.getenv("ANDROID_ROOT"));
         environment.add("ANDROID_DATA=" + System.getenv("ANDROID_DATA"));
         // EXTERNAL_STORAGE is needed for /system/bin/am to work on at least