add script to publish from tag

Signed-off-by: Maximilian Huber <maximilian.huber@tngtech.com>

publish_from_tag.sh

@@ -0,0 +1,50 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+if [ $# -eq 0 ]; then
+    cat<<EOF
+Usage:
+  $0 \$VERSION
+Example:
+  $0 0.8.0rc2
+where 0.8.0rc2 is the version and v0.8.0rc2 is the corresponding tag.
+EOF
+    exit 0
+fi
+
+
+version="$1"
+tag="v${version}"
+tar_gz="https://github.com/spdx/tools-python/releases/download/${tag}/spdx_tools_dist.tar.gz"
+tag_dir="dist-${tag}"
+
+cd -- "$(dirname "$0")"
+
+if ! command -v twine &> /dev/null; then
+    echo "twine could not be found"
+    echo "maybe load venv with"
+    echo "  . ./venv/bin/activate"
+    echo "  . ./venv/bin/activate.fish"
+    echo
+    echo "will try to avtivate..."
+
+    source ./venv/bin/activate
+fi
+
+
+if [[ -d "$tag_dir" ]]; then
+    echo "the dir \"$tag_dir\" already exists, exiting for safety"
+    exit 1
+fi
+
+mkdir -p "$tag_dir"
+(cd "$tag_dir" && wget -c "$tar_gz" -O - | tar --strip-components=1 -xz)
+
+twine check "${tag_dir}/spdx-tools-${version}.tar.gz"  "${tag_dir}/spdx_tools-${version}-py3-none-any.whl"
+read -r -p "Do you want to upload? [y/N] " response
+case "$response" in
+    [yY][eE][sS]|[yY])
+        twine upload -r pypi "${tag_dir}/spdx-tools-${version}.tar.gz"  "${tag_dir}/spdx_tools-${version}-py3-none-any.whl"
+        ;;
+esac