message: docs: Add missing npm install command to CLI examples
diff: @@ -77,6 +77,7 @@ it in the GRT contract:
  ```bash
  git clone https://github.com/graphprotocol/contracts
  cd contracts
  +npm install # if you haven't done this before
  ./cli/cli.ts -m <indexer-mnemonic> -p <ethereum-rinkeby-node> \
  contracts graphToken approve --account 0x2d44C0e097F6cD0f514edAC633d82E01280B4A5c --amount <grt>
  @@ -87,6 +88,7 @@ Afterwards, stake this amount:
  ```bash
  git clone https://github.com/graphprotocol/contracts
  cd contracts
  +npm install # if you haven't done this before
  ./cli/cli.ts -m <indexer-mnemonic> -p <ethereum-rinkeby-node> \
  contracts staking stake --amount <grt>
  @@ -100,6 +102,7 @@ This is similar to using Remix, except it's easier.
  ```bash
  git clone https://github.com/graphprotocol/contracts
  cd contracts
  +npm install # if you haven't done this before
  ./cli/cli.ts -m <indexer-mnemonic> -p <ethereum-rinkeby-node> \
  contracts staking setOperator --operator <operator-address> --allowed true
  