switch to go mod (#3613)

* Update to using go mod from dep

* Remove references to make get_vendor_deps

* Specify go version

* Set GO111MODULE=on and add -mod=readonly

* Fix exported env

* switch to using go1.12 everywhere

* Fix test scripts

* Typo:

* Prepend GO111MODULE=on

* remove dep cache

* Revert "remove dep cache"

This reverts commit 45117bda

Signed-off-by: Ismail Khoffi <Ismail.Khoffi@gmail.com>

* bring back the dependency cache and change it to cache modules instead
of vendored deps; also:

 - bump version for dependency cache
 - bump version on pkg-cache (includes modules directory)

Signed-off-by: Ismail Khoffi <Ismail.Khoffi@gmail.com>

* remove some more traces of dep:
 - remove Gopkg.(toml | lock)
 - update contributing guidlines
 - set global default in circleci (GO111MODULE=on)

Signed-off-by: Ismail Khoffi <Ismail.Khoffi@gmail.com>

* global var failed for `test_cover` with
`go: unknown environment setting GO111MODULE=true`
although the var was `GO111MODULE: on`

Signed-off-by: Ismail Khoffi <Ismail.Khoffi@gmail.com>

* Changelog pending entry

Signed-off-by: Ismail Khoffi <Ismail.Khoffi@gmail.com>

* Add bbolt dependency to go.mod

Signed-off-by: Ismail Khoffi <Ismail.Khoffi@gmail.com>

* move -mod=readonly to build flags

scripts/dist.sh

@@ -31,9 +31,6 @@ XC_EXCLUDE=${XC_EXCLUDE:-" darwin/arm solaris/amd64 solaris/386 solaris/arm free
 # Make sure build tools are available.
 make get_tools
 
-# Get VENDORED dependencies
-make get_vendor_deps
-
 # Build!
 # ldflags: -s Omit the symbol table and debug information.
 #	         -w Omit the DWARF symbol table.

scripts/get_tools.sh

@@ -48,9 +48,6 @@ installFromGithub() {
 	echo ""
 }
 
-######################## COMMON TOOLS ########################################
-installFromGithub golang/dep 22125cfaa6ddc71e145b1535d4b7ee9744fefff2 cmd/dep
-
 ######################## DEVELOPER TOOLS #####################################
 installFromGithub gogo/protobuf 61dbc136cf5d2f08d68a011382652244990a53a9 protoc-gen-gogo
 

scripts/install/install_tendermint_arm.sh

@@ -32,7 +32,6 @@ git checkout $BRANCH
 # XXX: uncomment if branch isn't master
 # git fetch origin $BRANCH
 make get_tools
-make get_vendor_deps
 make install
 
 # the binary is located in $GOPATH/bin

scripts/install/install_tendermint_bsd.sh

@@ -47,7 +47,6 @@ cd "$GOPATH/src/$REPO"
 # build & install master
 git checkout $BRANCH
 gmake get_tools
-gmake get_vendor_deps
 gmake install
 
 # the binary is located in $GOPATH/bin

scripts/install/install_tendermint_osx.sh

@@ -37,5 +37,4 @@ git checkout $BRANCH
 # XXX: uncomment if branch isn't master
 # git fetch origin $BRANCH
 make get_tools
-make get_vendor_deps
 make install

scripts/install/install_tendermint_ubuntu.sh

@@ -41,7 +41,6 @@ git checkout $BRANCH
 # XXX: uncomment if branch isn't master
 # git fetch origin $BRANCH
 make get_tools
-make get_vendor_deps
 make install
 
 # the binary is located in $GOPATH/bin