Travis updates (organization)

[junderw]

See https://github.com/bitcoinjs/bolt11/issues/5#issuecomment-381479499

Travis support should mimic bitcoinjs-lib which has already been updated.

bech32
bip174
bip21
bip32
bip32-utils
bip32-wallet
bip38
bip39
bip44-constants
bip65
bip66
bip68
bip69
bitcoin-ops
bitcoinjs-lib
bitcoinjs-message
bitcoinjs.github.io
blkdat-stream
bolt11
bs58check
coinselect
indexd
merkle-lib
minimaldata
playground
private-bitcoin
pushdata-bitcoin
safe-transaction
tif
utxo
varuint-bitcoin
wif

[jasonandjay]

@junderw Is this issue still useful?