go 1.16 features

- use go embed instead of go-binary and remove all about old assets (go 1.16 feature)
- pin gox version (go 1.16 feature)
- update ci to go 1.16

script/check_assets.sh

@@ -1,10 +0,0 @@
-#!/bin/bash
-
-if grep -q 'go/src/github.com/sosedoff/pgweb' ./pkg/data/bindata.go
-then
-  echo "=========================================================="
-  echo "ERROR: Bindata contains development references to assets!"
-  echo "Fix with 'make assets' and commit the change."
-  echo "=========================================================="
-  exit 1
-fi

script/check_formatting.sh

@@ -1,8 +1,5 @@
 #!/bin/bash
 
-# Run the fmt on bindata so it does not trigger failure
-go fmt ./pkg/data/bindata.go > /dev/null
-
 # Get list of offending files
 files="$(go fmt ./pkg/...)"