Remove Travis CI (#5287)

polkadot/.travis.yml

-# Request an environment that provides sudo (that goes with larger containers)
-# and a minimal language environment.
-sudo: true
-language: minimal
-
-cache: cargo
-
-branches:
-  only:
-  - master
-
-env:
-  global:
-    - RUST_BACKTRACE=1
-  matrix:
-    - RUST_TOOLCHAIN=nightly TARGET=wasm
-    - RUST_TOOLCHAIN=stable TARGET=native
-
-before_install:
-  # Check how much space we've got on this machine.
-  - df -h
-
-script:
-  - ./ci/script.sh
-
-after_script:
-  # Check how much free disk space left after the build
-  - df -h

polkadot/ci/script.sh

-#!/usr/bin/env bash
-
-set -eux
-
-# Install rustup and the specified rust toolchain.
-curl https://sh.rustup.rs -sSf | sh -s -- --default-toolchain=$RUST_TOOLCHAIN -y
-
-# Load cargo environment. Specifically, put cargo into PATH.
-source ~/.cargo/env
-
-rustc --version
-rustup --version
-cargo --version
-
-case $TARGET in
-	"native")
-		sudo apt-get -y update
-		sudo apt-get install -y cmake pkg-config libssl-dev
-
-		cargo test --all --locked "$@"
-		;;
-
-	"wasm")
-		# Install prerequisites and build all wasm projects
-		./scripts/init.sh
-		./scripts/build.sh --locked "$@"
-		;;
-esac