Remove i686 from arch=()

FTR, commands used to change arch=() and then verify the changes:

$ sed -Ei "/^arch=/{s/ *?['\"]?i686['\"]? *?//;s/ *$//}" */*/PKGBUILD*

$ grep -r i686 * | grep arch= | grep -v repos

$ svn diff | grep -A 1 ^-[^-] | grep -v -- -- | cut -c2- |
  while IFS=$'\n' read -r l1; IFS=$'\n' read -r l2; do
    echo "$l1 -> $l2"
  done | sort -u

PKGBUILD

@@ -9,7 +9,7 @@ pkgdesc='Disk usage analyzer with an ncurses interface'
 url='https://dev.yorhel.nl/ncdu'
 license=('custom:MIT')
 depends=('ncurses')
-arch=('i686' 'x86_64')
+arch=('x86_64')
 validpgpkeys=('74460D32B80810EBA9AFA2E962394C698C2739FA')
 source=("https://dev.yorhel.nl/download/${pkgname}-${pkgver}.tar.gz"{,.asc})
 sha256sums=('820e4e4747a2a2ec7a2e9f06d2f5a353516362c22496a10a9834f871b877499a'