A little change to pkgdesc. Removed unused fields. Pass a VERSION var to make. Added a v prefix for tag and made use of pkgver. pkgrel was incremented.

build/archlinux/PKGBUILD

@@ -1,30 +1,23 @@
 # Maintainer: Alexander "Arav" Andreev <me@arav.su>
 pkgname=justcaptcha
 pkgver=2.0.2
-pkgrel=1
-pkgdesc="Just a CAPTCHA service"
+pkgrel=2
+pkgdesc="Just a standalone simple CAPTCHA service"
 arch=('i686' 'x86_64' 'arm' 'armv6h' 'armv7h' 'aarch64')
 url="https://git.arav.su/Arav/justcaptcha"
 license=('MIT')
-groups=()
-depends=()
 makedepends=('go')
 provides=('justcaptcha')
 conflicts=('justcaptcha')
-replaces=()
-backup=()
-options=()
-install=
-source=('https://git.arav.su/Arav/justcaptcha/archive/2.0.2.tar.gz')
-noextract=()
+source=("https://git.arav.su/Arav/justcaptcha/archive/v${pkgver}.tar.gz")
 md5sums=('SKIP')
 
 build() {
     cd "$srcdir/$pkgname"
-    make DESTDIR="$pkgdir/"
+    make VERSION=$pkgver DESTDIR="$pkgdir/"
 }
 
 package() {
     cd "$srcdir/$pkgname"
-    make DESTDIR="$pkgdir/" install
+    make VERSION=$pkgver DESTDIR="$pkgdir/" install
 }