Added missing list braces (The-OpenROAD-Project#895)

~ Fix a failure when `MACRO_BLOCKAGES_LAYER` contains an even number of elements
~ Pin versions of `black`, `flake8`

Remove def2spef/SPEF Extractor (The-OpenROAD-Project#894)

Remove an unproven and oft unused utility from the OpenLane tree.

Update OpenROAD to HEAD (The-OpenROAD-Project#890)

- also removed second git yum install

PDK-Genericity Fixes (The-OpenROAD-Project#883)

+ PDK now overridable via `override_env` and environment
+ Added mergeLib.py to merge liberty files for PDKs that require multiple liberty files
~ Make FP_IO_MIN_DISTANCE optional
- Removed legacy OpenPhySyn variables

Add Python Linting (The-OpenROAD-Project#876)

+ Added linting rules for flake8, formatting with black
+ Added a GitHub Action to enforce lint/format rules

Fix Run Designs (The-OpenROAD-Project#874)

Move reading SDC file earlier (The-OpenROAD-Project#871)

I noticed that global routing reports 0 clock nets:

[INFO GRT-0019] Found 0 clock nets.

Moving the reading of the SDC file earlier fixes it:

[INFO GRT-0019] Found 980 clock nets.

Fix for make pdk (The-OpenROAD-Project#861)

[skip ci]

Signed-off-by: Vitor Bandeira <[email protected]>

Assorted Fixes To Error Reporting System (The-OpenROAD-Project#854)

+ Warnings now printed by flow_fail and at the end of noninteractive flow runs
+ Created warnings.log, errors.log with all warnings and errors
+ Get Tag now returns a dummy tag if you're on a branch that's not `main` or `master`
~ Tarballing moved to run_tests.py
~ Restored `-u` permissions to run_test.py.
~ Version mismatches now cause the flow to fail, straight up
~ flow_summary.log -> openlane.log
~ Various warning messages updated
~ Version checking moved to `prep`
~ change .bashrc CWD color to green (black was not readable)
~ `return -code error` added to flow_fail, removed after all flow_fail invocations
~ `make pdk` fixed
- Removed `--tar_list` from run_designs.py - do your own tarring

Add an ECO Flow for hold timing violations fixes (The-OpenROAD-Projec…

…t#791)

ECO flow starts from checking the report generated in the route step. As PT commands are not supported by OL, we use a python script to check the report, insert buffers, and do the resize. Inside the ECO loop, the python script, cts and route step are called sequentially. The reports are generated each time, and the loop stops until no hold time violations are found. 

The flow can be enabled using ECO_ENABLE =1.

More documentation and enhancements to come in the future.

Co-authored-by: Ke-Haur Taur <[email protected]>
Co-authored-by: Haolin Dong <[email protected]>