minor script fixes

mypy has no fix function so it shouldn't be called as part of the fix
process.

scripts/build

@@ -1,5 +1,7 @@
 #!/bin/sh -eu
 
+tag=latest
+
 cd "$RUN_DIR"
 
 contextdir="$RUN_DIR"/docker
@@ -12,4 +14,4 @@ fi
 
 set -x
 
-docker build "$@" --tag "$image":latest "$contextdir"
+docker build "$@" --tag "$image":"$tag" "$contextdir"

scripts/lint

@@ -13,7 +13,6 @@ if [ "$1" = '--fix' ]; then
         autoflake --in-place --recursive $autoflake_opts .
         black .
         isort --profile black .
-        mypy . || :  # ignore
     )
     exit
 fi