ci: use heredoc and alpine/edge for faster sr.ht job

ci/srht/on_master_success

@@ -4,6 +4,7 @@
 # It assumes that the following things are installed:
 # * curl
 # * jq
+# * cat
 
 set -x
 set -e
@@ -12,17 +13,19 @@ VERSION="$1"
 OAUTH_TOKEN="$2"
 YML_FILE="tmp.yml"
 
-echo "image: ubuntu/xenial" >> "$YML_FILE"
-echo "packages:" >> "$YML_FILE"
-echo "  - s3cmd" >> "$YML_FILE"
-echo "  - curl" >> "$YML_FILE"
-echo "  - jq" >> "$YML_FILE"
-echo "secrets:" >> "$YML_FILE"
-echo "  - 6c60aaee-92e7-4e7d-812c-114817689b4d" >> "$YML_FILE"
-echo "sources:" >> "$YML_FILE"
-echo "  - https://github.com/ziglang/zig" >> "$YML_FILE"
-echo "tasks:" >> "$YML_FILE"
-echo "  - build: cd zig && ./ci/srht/update_download_page $VERSION" >> "$YML_FILE"
+cat <<EOF >"$YML_FILE"
+image: alpine/edge
+packages:
+  - py3-pip
+  - curl
+  - jq
+secrets:
+  - 6c60aaee-92e7-4e7d-812c-114817689b4d
+sources:
+  - https://github.com/ziglang/zig
+tasks:
+  - build: cd zig && ./ci/srht/update_download_page $VERSION
+EOF
 
 jq <$YML_FILE -sR '{
       "manifest": .,

ci/srht/update_download_page

@@ -23,6 +23,7 @@ curl --fail -I "$X86_64_WINDOWS_JSON_URL" || exit 0
 curl --fail -I "$X86_64_MACOS_JSON_URL" || exit 0
 curl --fail -I "$X86_64_FREEBSD_JSON_URL" || exit 0
 
+pip3 install s3cmd
 rm -rf .git
 
 cd "$HOME"