Update examples with rgbpp package and env variables test

https://github.com/ckb-cell/rgbpp-sdk/pull/159

xudt-on-ckb

[x] 1-issue-xudt

xUDT asset on CKB has been issued and tx hash is 0xe6e23718e45a9c36136367dfb1c47397a7b3db2ff130a1c062f40c795f0b103d

https://pudge.explorer.nervos.org/transaction/0xe6e23718e45a9c36136367dfb1c47397a7b3db2ff130a1c062f40c795f0b103d

xUDT type script {
  codeHash: '0x25c29dc317811a6f6f3985a7a9ebc4838bd388d19d0feeecf0bcd60f6c0975bb',
  hashType: 'type',
  args: '0x8c556e92974a8dd8237719020a259d606359ac2cc958cb8bda77a1c3bb3cd93b'
}

[x] 2-transfer-xudt

xUDT asset has been minted or transferred and tx hash is 0x238224236164a74c76550817679914b7cc510740ded11a71d10ba0ac75e19993

https://pudge.explorer.nervos.org/transaction/0x238224236164a74c76550817679914b7cc510740ded11a71d10ba0ac75e19993?addr_format=deprecated

xudt

[x] 1-ckb-leap-btc

Rgbpp asset has been jumped from CKB to BTC and tx hash is 0x9887ae9459e25ec4a89acf2895c3ca100db6b2f4428f732e653b42e9729cac6d

https://pudge.explorer.nervos.org/transaction/0x9887ae9459e25ec4a89acf2895c3ca100db6b2f4428f732e653b42e9729cac6d

[x] 2-btc-transfer

BTC TxId: 2070426de01105481cf568d916aeac932921ba190c81ad46bb5b2b3e06bcc262