Improve CircleCI config

Author: dochang

.circleci/config.yml

@@ -53,12 +53,11 @@ jobs:
           # https://daniel.haxx.se/blog/2020/06/24/curl-7-71-0-blobs-and-retries/
           # https://curl.se/docs/manpage.html#--retry-all-errors
           command: |
-            CODECOV_BIN="$(mktemp -d)/codecov/bin"
+            CODECOV="$(mktemp -d)/codecov/bin/codecov"
             # `mktemp` on codecov doesn't support long options, use short
             # options instead.
 
-            CODECOV="${CODECOV_BIN}/codecov"
-            curl --output "${CODECOV}" --create-dirs --silent --show-error https://cli.codecov.io/latest/linux/codecov
+            curl --output "${CODECOV}" --create-dirs --location --silent --show-error https://cli.codecov.io/latest/linux/codecov
             chmod +x "${CODECOV}"
 
             "${CODECOV}" upload-process --file coverage.txt --slug "${CIRCLE_PROJECT_USERNAME}/${CIRCLE_PROJECT_REPONAME}"