version: Update version for Zulip Desktop v5.4.0 release.
version: Update version for Zulip Desktop v5.4.0 release.

Update the zulip-desktop download link for the latest v5.4.0 release
This commit only updates zulipchat.com/apps/ links.

brainwane/zulip,showell/zulip,showell/zulip,hackerkid/zulip,zulip/zulip,kou/zulip,andersk/zulip,punchagan/zulip,punchagan/zulip,showell/zulip,kou/zulip,zulip/zulip,punchagan/zulip,punchagan/zulip,brainwane/zulip,rht/zulip,rht/zulip,brainwane/zulip,kou/zulip,zulip/zulip,hackerkid/zulip,rht/zulip,eeshangarg/zulip,punchagan/zulip,zulip/zulip,rht/zulip,zulip/zulip,rht/zulip,eeshangarg/zulip,zulip/zulip,showell/zulip,showell/zulip,showell/zulip,andersk/zulip,punchagan/zulip,andersk/zulip,brainwane/zulip,andersk/zulip,rht/zulip,kou/zulip,hackerkid/zulip,eeshangarg/zulip,hackerkid/zulip,andersk/zulip,zulip/zulip,andersk/zulip,kou/zulip,eeshangarg/zulip,brainwane/zulip,eeshangarg/zulip,andersk/zulip,punchagan/zulip,brainwane/zulip,eeshangarg/zulip,hackerkid/zulip,hackerkid/zulip,kou/zulip,hackerkid/zulip,showell/zulip,kou/zulip,eeshangarg/zulip,brainwane/zulip,rht/zulip